115 results on '"Chalifa-Caspi V"'
Search Results
2. A real-time PCR for specific detection of the Legionella pneumophila serogroup 1 ST1 complex
- Author
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Ginevra, C., Chastang, J., David, S., Mentasti, M., Yakunin, E., Chalker, V.J., Chalifa-Caspi, V., Valinsky, L., Jarraud, S., and Moran-Gilad, J.
- Published
- 2020
- Full Text
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3. Pollution-Affected Fish Hepatic Transcriptome and Its Expression Patterns on Exposure to Cadmium
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Auslander, M., Yudkovski, Y., Chalifa-Caspi, V., Herut, B., Ophir, R., Reinhardt, R., Neumann, P. M., and Tom, M.
- Published
- 2008
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4. BRD4 methylation by the methyltransferase SETD6 regulates selective transcription to control mRNA translation
- Author
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Vershinin, Z, Feldman, M, Werner, T, Wei, LE, Kublanovsky, M, Abaev-Schneiderman, E, Sklarz, M, Lam, EYN, Alasad, K, Picaud, S, Rotblat, B, McAdam, RA, Chalifa-Caspi, V, Bantscheff, M, Chapman, T, Lewis, HD, Filippakopoulos, P, Dawson, MA, Grandi, P, Prinjha, RK, Levy, D, Vershinin, Z, Feldman, M, Werner, T, Wei, LE, Kublanovsky, M, Abaev-Schneiderman, E, Sklarz, M, Lam, EYN, Alasad, K, Picaud, S, Rotblat, B, McAdam, RA, Chalifa-Caspi, V, Bantscheff, M, Chapman, T, Lewis, HD, Filippakopoulos, P, Dawson, MA, Grandi, P, Prinjha, RK, and Levy, D
- Abstract
The transcriptional coactivator BRD4 has a fundamental role in transcription regulation and thus became a promising epigenetic therapeutic candidate to target diverse pathologies. However, the regulation of BRD4 by posttranslational modifications has been largely unexplored. Here, we show that BRD4 is methylated on chromatin at lysine-99 by the protein lysine methyltransferase SETD6. BRD4 methylation negatively regulates the expression of genes that are involved in translation and inhibits total mRNA translation in cells. Mechanistically, we provide evidence that supports a model where BRD4 methylation by SETD6 does not have a direct role in the association with acetylated histone H4 at chromatin. However, this methylation specifically determines the recruitment of the transcription factor E2F1 to selected target genes that are involved in mRNA translation. Together, our findings reveal a previously unknown molecular mechanism for BRD4 methylation-dependent gene-specific targeting, which may serve as a new direction for the development of therapeutic applications.
- Published
- 2021
5. Glycolytic enzymes associated with the cell surface of Streptococcus pneumoniae are antigenic in humans and elicit protective immune responses in the mouse
- Author
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LING, E., FELDMAN, G., PORTNOI, M., DAGAN, R., OVERWEG, K., MULHOLLAND, F., CHALIFA-CASPI, V., WELLS, J., and MIZRACHI-NEBENZAHL, Y.
- Published
- 2004
6. Whole genome expression patterns: the importance of being suppressed
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Lancet, D., Benjamin-Rodrig, H., Shmoish, M., Chalifa-Caspi, V., Shklar, M., Ophir, R., Bar-Even, A., Horn-Saban, S., Safran, M., Domany, E., Yanai, I., and Shmueli, O.
- Published
- 2004
7. African descents are more sensitive than European descents to the antitumor compounds alpha-Hederin and kalopanaxsaponin I
- Author
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Feller, G., Kugel, A., Moonshine, D., Chalifa-Caspi, V., Scholz, M., Prüfer, D., Rabinski, T., Müller, K.J., Ofir, R., and Publica
- Abstract
alpha-Hederin, a natural triterpene saponin and its derivative kalopanaxsaponin I (ksI) exhibit cytotoxicity against various cancer cell lines and in vivo tumors. We studied the genetic variants contributing to the activity of these two anticancer compounds. Cell lines derived from 30 trios of European descent (Centre d'Etude du Polymor-phisme Human, CEPH; CEU) and 30 trios of African descent (Yoruban, YRI) were used. Cytotoxicity was determined as inhibition of cell growth at increasing concentrations of alpha-hederin or ksI for 24 h. In comparison to the European, the Yoruban populations revealed a higher sensitivity to alpha-hederin and to ksI that can be attributed to several unique SNPs. These SNPs are located near 111 and 130 genes in the European and the Yoruban populations, respectively, raising the possibility that some of these genes contribute to the differential sensitivity to these compounds.
- Published
- 2010
8. Gene expression microarray profiles of cumulus cells in lean and overweight-obese polycystic ovary syndrome patients
- Author
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Kenigsberg, S., primary, Bentov, Y., additional, Chalifa-Caspi, V., additional, Potashnik, G., additional, Ofir, R., additional, and Birk, O. S., additional
- Published
- 2008
- Full Text
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9. Hepatopancreatic multi-transcript expression patterns in the crayfish Cherax quadricarinatus during the moult cycle
- Author
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Yudkovski, Y., primary, Shechter, A., additional, Chalifa-Caspi, V., additional, Auslander, M., additional, Ophir, R., additional, Dauphin-Villemant, C., additional, Waterman, M., additional, Sagi, A., additional, and Tom, M., additional
- Published
- 2007
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10. GeneAnnot: Interfacing GeneCards with high-throughput gene expression compendia
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Chalifa-Caspi, V., primary
- Published
- 2003
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11. GeneCards: a novel functional genomics compendium with automated data mining and query reformulation support.
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Rebhan, M, primary, Chalifa-Caspi, V, additional, Prilusky, J, additional, and Lancet, D, additional
- Published
- 1998
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12. Glycolytic enzymes associated with the cell surface ofStreptococcus pneumoniaeare antigenic in humans and elicit protective immune responses in the mouse.
- Author
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LING, E., FELDMAN, G., PORTNOI, M., DAGAN, R., OVERWEG, K., MULHOLLAND, F., CHALIFA-CASPI, V., WELLS, J., and MIZRACHI-NEBENZAHL, Y.
- Subjects
STREPTOCOCCUS pneumoniae ,PNEUMOCOCCAL vaccines ,LUNG diseases ,NEISSERIA meningitidis ,IMMUNE response ,GEL electrophoresis ,HEAT shock proteins - Abstract
Streptococcus pneumoniaeis a leading cause of otitis media, sinusitis, pneumonia, bacteraemia and meningitis worldwide. The drawbacks associated with the limited number of various capsular polysaccharides that can be included in the polysaccharide-based vaccines focuses much attention on pneumococcal proteins as vaccine candidates. We extracted an enriched cell wall fraction fromS. pneumoniaeWU2. Approximately 150 soluble proteins could be identified by 2D gel electrophoresis. The proteins were screened by 2D-Western blotting using sera that were obtained longitudinally from children attending day-care centres at 18, 30 and 42 months of age and sera from healthy adult volunteers. The proteins were further identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry. Seventeen proteins were antigenic in children and adults, of which 13 showed an increasing antibody response with age in all eight children analysed. Two immunogenic proteins, fructose–bisphosphate aldolase (FBA) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and a control protein with known low immunogenicity, heat shock protein 70 (DnaK), were expressed inEscherichia coli, purified and used to immunize mice. Mouse antibodies elicited to the recombinant (r) FBA and rGAPDH were cross-reactive with several genetically unrelated strains of different serotypes and conferred protection to respiratory challenge with virulent pneumococci. In addition, the FBA used in this study (NP_345117) does not have a human ortholog and warrants further investigation as a candidate for a pneumococcal vaccine. In conclusion, the immunoproteomics based approach utilized in the present study appears to be a suitable tool for identification of novelS. pneumoniaevaccine candidates. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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13. Enzymology of mammalian phospholipases D: in vitro studies
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Liscovitch, M. and Chalifa-Caspi, V.
- Published
- 1996
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14. KinSNP software for homozygosity mapping of disease genes using SNP microarrays
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Amir El-Ad, Bartal Ofer, Morad Efrat, Nagar Tal, Sheynin Jony, Parvari Ruti, and Chalifa-Caspi Vered
- Subjects
autozygosity ,consanguinity ,genetic mapping ,homozygosity ,SNP microarrays ,software ,Medicine ,Genetics ,QH426-470 - Abstract
Abstract Consanguineous families affected with a recessive genetic disease caused by homozygotisation of a mutation offer a unique advantage for positional cloning of rare diseases. Homozygosity mapping of patient genotypes is a powerful technique for the identification of the genomic locus harbouring the causing mutation. This strategy relies on the observation that in these patients a large region spanning the disease locus is also homozygous with high probability. The high marker density in single nucleotide polymorphism (SNP) arrays is extremely advantageous for homozygosity mapping. We present KinSNP, a user-friendly software tool for homozygosity mapping using SNP arrays. The software searches for stretches of SNPs which are homozygous to the same allele in all ascertained sick individuals. User-specified parameters control the number of allowed genotyping 'errors' within homozygous blocks. Candidate disease regions are then reported in a detailed, coloured Excel file, along with genotypes of family members and healthy controls. An interactive genome browser has been included which shows homozygous blocks, individual genotypes, genes and further annotations along the chromosomes, with zooming and scrolling capabilities. The software has been used to identify the location of a mutated gene causing insensitivity to pain in a large Bedouin family. KinSNP is freely available from http://bioinfo.bgu.ac.il/bsu/software/kinSNP.
- Published
- 2010
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15. GeneLoc: exon-based integration of human genome maps
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Rosen, N., Chalifa-Caspi, V., Shmueli, O., Adato, A., Lapidot, M., Stampnitzky, J., Safran, M., and Lancet, D.
- Abstract
Motivation:Despite the numerous available whole-genome mapping resources, no comprehensive, integrated map of the human genome yet exists. Results: GeneLoc, software adjunct to GeneCards and UDB, integrates gene lists by comparing genomic coordinates at the exon level and assigns unique and meaningful identifiers to each gene.Availability: http://bioinfo.weizmann.ac.il/genecards and http://genecards.weizmann.ac.il/udbSupplementary information: http://bioinfo.weizmann.ac.il/cards-bin/AboutGCids.cgi, http://genecards.weizmann.ac.il/GeneLocAlg.htmlContact: marilyn.safran@weizmann.ac.il
- Published
- 2003
16. GeneCards/spl trade/ 2002: an evolving human gene compendium
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Safran, M., primary, Solomon, I., additional, Shmueli, O., additional, Lapidot, M., additional, Shen-Orr, S., additional, Adato, A., additional, Ben-Dor, U., additional, Esterman, N., additional, Rosen, N., additional, Peter, I., additional, Olender, T., additional, Chalifa-Caspi, V., additional, and Lancet, D., additional
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17. GeneCards™ 2002: an evolving human gene compendium.
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Safran, M., Solomon, I., Shmueli, O., Lapidot, M., Shen-Orr, S., Adato, A., Ben-Dor, U., Esterman, N., Rosen, N., Peter, I., Olender, T., Chalifa-Caspi, V., and Lancet, D.
- Published
- 2002
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18. GeneCards: integrating information about genes, proteins and diseases
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Rebban, M., Chalifa-Caspi, V., Prilusky, J., and Lancet, D.
- Published
- 1997
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19. Protandric Transcriptomes to Uncover Parts of the Crustacean Sex-Differentiation Puzzle
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Tom Levy, Valerio Zupo, Mirko Mutalipassi, Emanuele Somma, Nadia Ruocco, Maria Costantini, Shai Abehsera, Rivka Manor, Vered Chalifa-Caspi, Amir Sagi, Eliahu D. Aflalo, Levy, T., Zupo, V., Mutalipassi, M., Somma, E., Ruocco, N., Costantini, M., Abehsera, S., Manor, R., Chalifa-Caspi, V., Sagi, A., and Aflalo, E. D.
- Subjects
0106 biological sciences ,Science ,Ocean Engineering ,Aquatic Science ,Biology ,QH1-199.5 ,Oceanography ,010603 evolutionary biology ,01 natural sciences ,Transcriptome ,03 medical and health sciences ,Vitellogenin ,Hippolyte inermi ,hermaphrodite ,Hermaphrodite ,protandry ,Hippolyte inermis ,Reproductive system ,Gene ,030304 developmental biology ,Water Science and Technology ,0303 health sciences ,Global and Planetary Change ,Sexual differentiation ,Pandalus platyceros ,General. Including nature conservation, geographical distribution ,biology.organism_classification ,Crustacean ,Shrimp ,IAG-switch ,Pandalus platycero ,Evolutionary biology ,reproductive physiology ,androgenic gland ,sex-differentiation ,biology.protein - Abstract
Hermaphrodite systems offer unique opportunities to study sexual differentiation, due to their high degree of sexual plasticity and to the fact that, unlike gonochoristic systems, the process is not confined to an early developmental stage. In protandric shrimp species, such as Hippolyte inermis and Pandalus platyceros, male differentiation is followed by transformation to femaleness during adulthood. The mechanisms controlling sexual differentiation have not been fully elucidated in crustaceans, but a key role has been attributed to the insulin-like hormone (IAG) produced by the androgenic gland (AG), a crustacean masculine endocrine organ. To uncover further transcriptomic toolkit elements affecting the sexual differentiation of H. inermis, we constructed eye and whole body RNA libraries of four representative stages during its protandric life cycle (immature, male, young female and mature female). The body libraries contained transcripts related to the reproductive system, among others, while the eye libraries contained transcripts related to the X-organ-sinus gland, a central endocrine complex that regulates crustacean reproduction. Binary pattern analysis, performed to mine for genes expressed differentially between the different life stages, yielded 19,605 and 6,175 transcripts with a specific expression pattern in the eye and body, respectively. Prominent sexually biased transcriptomic patterns were recorded for the IAG and vitellogenin genes, representing, respectively, a key factor within the masculine IAG-switch, and a precursor of the yolk protein, typical of feminine reproductive states. These patterns enabled the discovery of novel putative protein-coding transcripts exhibiting sexually biased expression in the H. inermis body and eye transcriptomes of males and females. Homologs to the above novel genes have been found in other decapod crustaceans, and a comparative study, using previously constructed transcriptomic libraries of another protandric shrimp, P. platyceros, showed similar sexually biased results, supporting the notion that such genes, mined from the H. inermis transcriptome, may be universal factors related to reproduction and sexual differentiation and their control in other crustaceans. This study thus demonstrates the potential of transcriptomic studies in protandric species to uncover unexplored layers of the complex crustacean sex-differentiation puzzle.
- Published
- 2021
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20. Roadmap and Considerations for Genome Editing in a Non-Model Organism: Genetic Variations and Off-Target Profiling.
- Author
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Wattad H, Molcho J, Manor R, Weil S, Aflalo ED, Chalifa-Caspi V, and Sagi A
- Subjects
- Animals, Palaemonidae genetics, Genetic Variation, Polymorphism, Single Nucleotide, High-Throughput Nucleotide Sequencing, Molecular Sequence Annotation, Sex Chromosomes genetics, Gene Editing methods, CRISPR-Cas Systems
- Abstract
The CRISPR/Cas genome editing approach in non-model organisms poses challenges that remain to be resolved. Here, we demonstrated a generalized roadmap for a de novo genome annotation approach applied to the non-model organism Macrobrachium rosenbergii . We also addressed the typical genome editing challenges arising from genetic variations, such as a high frequency of single nucleotide polymorphisms, differences in sex chromosomes, and repetitive sequences that can lead to off-target events. For the genome editing of M. rosenbergii , our laboratory recently adapted the CRISPR/Cas genome editing approach to embryos and the embryonic primary cell culture. In this continuation study, an annotation pipeline was trained to predict the gene models by leveraging the available genomic, transcriptomic, and proteomic data, and enabling accurate gene prediction and guide design for knock-outs. A next-generation sequencing analysis demonstrated a high frequency of genetic variations in genes on both autosomal and sex chromosomes, which have been shown to affect the accuracy of editing analyses. To enable future applications based on the CRISPR/Cas tool in non-model organisms, we also verified the reliability of editing efficiency and tracked off-target frequencies. Despite the lack of comprehensive information on non-model organisms, this study provides an example of the feasibility of selecting and editing specific genes with a high degree of certainty.
- Published
- 2024
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21. Tissue-aware interpretation of genetic variants advances the etiology of rare diseases.
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Argov CM, Shneyour A, Jubran J, Sabag E, Mansbach A, Sepunaru Y, Filtzer E, Gruber G, Volozhinsky M, Yogev Y, Birk O, Chalifa-Caspi V, Rokach L, and Yeger-Lotem E
- Subjects
- Humans, Organ Specificity genetics, Genetic Predisposition to Disease, Computational Biology methods, Rare Diseases genetics, Machine Learning, Genetic Variation
- Abstract
Pathogenic variants underlying Mendelian diseases often disrupt the normal physiology of a few tissues and organs. However, variant effect prediction tools that aim to identify pathogenic variants are typically oblivious to tissue contexts. Here we report a machine-learning framework, denoted "Tissue Risk Assessment of Causality by Expression for variants" (TRACEvar, https://netbio.bgu.ac.il/TRACEvar/ ), that offers two advancements. First, TRACEvar predicts pathogenic variants that disrupt the normal physiology of specific tissues. This was achieved by creating 14 tissue-specific models that were trained on over 14,000 variants and combined 84 attributes of genetic variants with 495 attributes derived from tissue omics. TRACEvar outperformed 10 well-established and tissue-oblivious variant effect prediction tools. Second, the resulting models are interpretable, thereby illuminating variants' mode of action. Application of TRACEvar to variants of 52 rare-disease patients highlighted pathogenicity mechanisms and relevant disease processes. Lastly, the interpretation of all tissue models revealed that top-ranking determinants of pathogenicity included attributes of disease-affected tissues, particularly cellular process activities. Collectively, these results show that tissue contexts and interpretable machine-learning models can greatly enhance the etiology of rare diseases., (© 2024. The Author(s).)
- Published
- 2024
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22. sNucConv: A bulk RNA-seq deconvolution method trained on single-nucleus RNA-seq data to estimate cell-type composition of human adipose tissues.
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Sorek G, Haim Y, Chalifa-Caspi V, Lazarescu O, Ziv-Agam M, Hagemann T, Nono Nankam PA, Blüher M, Liberty IF, Dukhno O, Kukeev I, Yeger-Lotem E, Rudich A, and Levin L
- Abstract
Deconvolution algorithms mostly rely on single-cell RNA-sequencing (scRNA-seq) data applied onto bulk RNA-sequencing (bulk RNA-seq) to estimate tissues' cell-type composition, with performance accuracy validated on deposited databases. Adipose tissues' cellular composition is highly variable, and adipocytes can only be captured by single-nucleus RNA-sequencing (snRNA-seq). Here we report the development of sNucConv, a Scaden deep-learning-based deconvolution tool, trained using 5 hSAT and 7 hVAT snRNA-seq-based data corrected by (i) snRNA-seq/bulk RNA-seq highly correlated genes and (ii) individual cell-type regression models. Applying sNucConv on our bulk RNA-seq data resulted in cell-type proportion estimation of 15 and 13 cell types, with accuracy of R = 0.93 (range: 0.76-0.97) and R = 0.95 (range: 0.92-0.98) for hVAT and hSAT, respectively. This performance level was further validated on an independent set of samples (5 hSAT; 5 hVAT). The resulting model was depot specific, reflecting depot differences in gene expression patterns. Jointly, sNucConv provides proof-of-concept for producing validated deconvolution models for tissues un-amenable to scRNA-seq., Competing Interests: The authors declare no competing interests., (© 2024 The Authors.)
- Published
- 2024
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23. A transcriptomic examination of encased rotifer embryos reveals the developmental trajectory leading to long-term dormancy; are they "animal seeds"?
- Author
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Hashimshony T, Levin L, Fröbius AC, Dahan N, Chalifa-Caspi V, Hamo R, Gabai-Almog O, Blais I, Assaraf YG, and Lubzens E
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- Animals, Gene Expression Profiling, Transcriptome, Proteins metabolism, Seeds, Plant Dormancy, Germination genetics, Rotifera genetics
- Abstract
Background: Organisms from many distinct evolutionary lineages acquired the capacity to enter a dormant state in response to environmental conditions incompatible with maintaining normal life activities. Most studied organisms exhibit seasonal or annual episodes of dormancy, but numerous less studied organisms enter long-term dormancy, lasting decades or even centuries. Intriguingly, many planktonic animals produce encased embryos known as resting eggs or cysts that, like plant seeds, may remain dormant for decades. Herein, we studied a rotifer Brachionus plicatilis as a model planktonic species that forms encased dormant embryos via sexual reproduction and non-dormant embryos via asexual reproduction and raised the following questions: Which genes are expressed at which time points during embryogenesis? How do temporal transcript abundance profiles differ between the two types of embryos? When does the cell cycle arrest? How do dormant embryos manage energy?, Results: As the molecular developmental kinetics of encased embryos remain unknown, we employed single embryo RNA sequencing (CEL-seq) of samples collected during dormant and non-dormant embryogenesis. We identified comprehensive and temporal transcript abundance patterns of genes and their associated enriched functional pathways. Striking differences were uncovered between dormant and non-dormant embryos. In early development, the cell cycle-associated pathways were enriched in both embryo types but terminated with fewer nuclei in dormant embryos. As development progressed, the gene transcript abundance profiles became increasingly divergent between dormant and non-dormant embryos. Organogenesis was suspended in dormant embryos, concomitant with low transcript abundance of homeobox genes, and was replaced with an ATP-poor preparatory phase characterized by very high transcript abundance of genes encoding for hallmark dormancy proteins (e.g., LEA proteins, sHSP, and anti-ROS proteins, also found in plant seeds) and proteins involved in dormancy exit. Surprisingly, this period appeared analogous to the late maturation phase of plant seeds., Conclusions: The study highlights novel divergent temporal transcript abundance patterns between dormant and non-dormant embryos. Remarkably, several convergent functional solutions appear during the development of resting eggs and plant seeds, suggesting a similar preparatory phase for long-term dormancy. This study accentuated the broad novel molecular features of long-term dormancy in encased animal embryos that behave like "animal seeds"., (© 2024. The Author(s).)
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- 2024
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24. Ferroptosis precedes apoptosis to facilitate specific death signalling by fatty acids.
- Author
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Zupo V, Costantini M, Aflalo ED, Levy T, Chalifa-Caspi V, Obayomi O, Mutalipassi M, Ruocco N, Glaviano F, Somma E, Nieri P, and Sagi A
- Subjects
- Animals, Fatty Acids, Apoptosis, Gene Expression Profiling, Crustacea, Ferroptosis, Diatoms
- Abstract
Cell death is physiologically induced by specific mediators. However, our power to trigger the process in selected cells is quite limited. The protandric shrimp Hippolyte inermis offers a possible answer. Here, we analyse a de novo transcriptome of shrimp post-larvae fed on diatoms. The sex ratio of diatom-fed shrimps versus shrimps fed on control diets was dramatically altered, demonstrating the disruption of the androgenic gland, and their transcriptome revealed key modifications in gene expression. A wide transcriptomic analysis, validated by real-time qPCR, revealed that ferroptosis represents the primary factor to re-shape the body of this invertebrate, followed by further apoptotic events, and our findings open biotechnological perspectives for controlling the destiny of selected tissues. Ferroptosis was detected here for the first time in a crustacean. In addition, this is the first demonstration of a noticeable effect prompted by an ingested food, deeply impacting the gene networks of a young metazoan, definitely determining its future physiology and sexual differentiation.
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- 2023
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25. Correction: Targeting the overexpressed mitochondrial protein VDAC1 in a mouse model of Alzheimer's disease protects against mitochondrial dysfunction and mitigates brain pathology.
- Author
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Verma A, Shteinfer-Kuzmine A, Kamenetsky N, Pittala S, Paul A, Nahon Crystal E, Ouro A, Chalifa-Caspi V, Pandey SK, Monsonego A, Vardi N, Knafo S, and Shoshan-Barmatz V
- Published
- 2023
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26. Targeting the overexpressed mitochondrial protein VDAC1 in a mouse model of Alzheimer's disease protects against mitochondrial dysfunction and mitigates brain pathology.
- Author
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Verma A, Shteinfer-Kuzmine A, Kamenetsky N, Pittala S, Paul A, Nahon Crystal E, Ouro A, Chalifa-Caspi V, Pandey SK, Monsonego A, Vardi N, Knafo S, and Shoshan-Barmatz V
- Subjects
- Mice, Animals, Mitochondrial Proteins, Amyloid beta-Peptides metabolism, Brain metabolism, Mitochondria metabolism, Alzheimer Disease drug therapy, Alzheimer Disease genetics, Alzheimer Disease metabolism
- Abstract
Background: Alzheimer's disease (AD) exhibits mitochondrial dysfunctions associated with dysregulated metabolism, brain inflammation, synaptic loss, and neuronal cell death. As a key protein serving as the mitochondrial gatekeeper, the voltage-dependent anion channel-1 (VDAC1) that controls metabolism and Ca
2+ homeostasis is positioned at a convergence point for various cell survival and death signals. Here, we targeted VDAC1 with VBIT-4, a newly developed inhibitor of VDAC1 that prevents its pro-apoptotic activity, and mitochondria dysfunction., Methods: To address the multiple pathways involved in AD, neuronal cultures and a 5 × FAD mouse model of AD were treated with VBIT-4. We addressed multiple topics related to the disease and its molecular mechanisms using immunoblotting, immunofluorescence, q-RT-PCR, 3-D structural analysis and several behavioral tests., Results: In neuronal cultures, amyloid-beta (Aβ)-induced VDAC1 and p53 overexpression and apoptotic cell death were prevented by VBIT-4. Using an AD-like 5 × FAD mouse model, we showed that VDAC1 was overexpressed in neurons surrounding Aβ plaques, but not in astrocytes and microglia, and this was associated with neuronal cell death. VBIT-4 prevented the associated pathophysiological changes including neuronal cell death, neuroinflammation, and neuro-metabolic dysfunctions. VBIT-4 also switched astrocytes and microglia from being pro-inflammatory/neurotoxic to neuroprotective phenotype. Moreover, VBIT-4 prevented cognitive decline in the 5 × FAD mice as evaluated using several behavioral assessments of cognitive function. Interestingly, VBIT-4 protected against AD pathology, with no significant change in phosphorylated Tau and only a slight decrease in Aβ-plaque load., Conclusions: The study suggests that mitochondrial dysfunction with its gatekeeper VDAC1 is a promising target for AD therapeutic intervention, and VBIT-4 is a promising drug candidate for AD treatment., (© 2022. The Author(s).)- Published
- 2022
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27. Positive selection and heat-response transcriptomes reveal adaptive features of the Brassicaceae desert model, Anastatica hierochuntica.
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Eshel G, Duppen N, Wang G, Oh DH, Kazachkova Y, Herzyk P, Amtmann A, Gordon M, Chalifa-Caspi V, Oscar MA, Bar-David S, Marshall-Colon A, Dassanayake M, and Barak S
- Subjects
- Acclimatization, Adaptation, Physiological genetics, Gene Expression Regulation, Plant, Transcriptome genetics, Arabidopsis genetics, Brassicaceae genetics
- Abstract
Plant adaptation to a desert environment and its endemic heat stress is poorly understood at the molecular level. The naturally heat-tolerant Brassicaceae species Anastatica hierochuntica is an ideal extremophyte model to identify genetic adaptations that have evolved to allow plants to tolerate heat stress and thrive in deserts. We generated an A. hierochuntica reference transcriptome and identified extremophyte adaptations by comparing Arabidopsis thaliana and A. hierochuntica transcriptome responses to heat, and detecting positively selected genes in A. hierochuntica. The two species exhibit similar transcriptome adjustment in response to heat and the A. hierochuntica transcriptome does not exist in a constitutive heat 'stress-ready' state. Furthermore, the A. hierochuntica global transcriptome as well as heat-responsive orthologs, display a lower basal and higher heat-induced expression than in A. thaliana. Genes positively selected in multiple extremophytes are associated with stomatal opening, nutrient acquisition, and UV-B induced DNA repair while those unique to A. hierochuntica are consistent with its photoperiod-insensitive, early-flowering phenotype. We suggest that evolution of a flexible transcriptome confers the ability to quickly react to extreme diurnal temperature fluctuations characteristic of a desert environment while positive selection of genes involved in stress tolerance and early flowering could facilitate an opportunistic desert lifestyle., (© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation.)
- Published
- 2022
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28. Visceral Adipose Tissue E2F1-miRNA206/210 Pathway Associates with Type 2 Diabetes in Humans with Extreme Obesity.
- Author
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Maixner N, Haim Y, Blüher M, Chalifa-Caspi V, Veksler-Lublinsky I, Makarenkov N, Yoel U, Bashan N, Liberty IF, Kukeev I, Dukhno O, Levy D, and Rudich A
- Subjects
- E2F1 Transcription Factor genetics, E2F1 Transcription Factor metabolism, Glucose metabolism, HEK293 Cells, Humans, Insulin metabolism, Intra-Abdominal Fat metabolism, Obesity genetics, Obesity metabolism, Diabetes Mellitus, Type 2 genetics, Diabetes Mellitus, Type 2 metabolism, MicroRNAs genetics, MicroRNAs metabolism
- Abstract
Objective: Up-regulated expression of transcription-factor E2F1 in human visceral adipose tissue (VAT) characterizes a dysmetabolic obesity sub-phenotype. An E2F1-miRNA network has been described in multiple cancers. Here we investigated whether elevated VAT-E2F1 in obesity is associated with VAT-miRNA alterations similar to, or distinct from, those described in cancer. Furthermore, we assessed if E2F1-associated miRNA changes may contribute to the link between high- VAT-E2F1 and a dysmetabolic obesity phenotype. Methods: We assembled a cohort of patients with obesity and high-VAT-E2F1, matched by age, sex, ±BMI to patients with low-VAT-E2F1, with and without obesity (8 patients/groupX3 groups). We performed Nanostring©-based miRNA profiling of VAT samples from all 24 patients. Candidate E2F1-related miRNAs were validated by qPCR in an independent cohort of patients with extreme obesity, with or without type-2-diabetes (T2DM) (n = 20). Bioinformatic tools and manipulation of E2F1 expression in cells were used to establish the plausibility of the functional VAT-E2F1-miRNA network in obesity. Results: Among n = 798 identified miRNAs, 17 were differentially expressed in relation to E2F1 and not to obesity itself. No evidence for the cancer-related E2F1-miRNA network was identified in human VAT in obesity. In HEK293-cells, overexpression/downregulation of E2F1 correspondingly altered the expression of miRNA-206 and miRNA-210-5p, two miRNAs with reported metabolic functions consistent with those of E2F1. In VAT from both cohorts, the expression of both miRNA-206 and 210-5p intercorrelated, and correlated with the expression of E2F1. In cohort 1 we did not detect significant associations with biochemical parameters. In cohort 2 of patients with extreme obesity, all those with high VAT-E2F1 showed a diabetes-complicated obesity phenotype and higher expression of miRNA-206 and miRNA-210-5p, which also correlated with fasting glucose levels (both miRNAs) and fasting insulin (miRNA-210-5p). Conclusions: Whilst the previously described cancer-related E2F1-miRNA network does not appear to operate in VAT in obesity, miRNAs-206 and 210-5p may link high-E2F1 expression in VAT with diabetes-complicated extreme obesity phenotype.
- Published
- 2022
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29. Non-apoptotic activity of the mitochondrial protein SMAC/Diablo in lung cancer: Novel target to disrupt survival, inflammation, and immunosuppression.
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Pandey SK, Shteinfer-Kuzmine A, Chalifa-Caspi V, and Shoshan-Barmatz V
- Abstract
Mitochondrial SMAC/Diablo induces apoptosis by binding the inhibitor of apoptosis proteins (IAPs), thereby activating caspases and, subsequently, apoptosis. Previously, we found that despite its pro-apoptotic activity, SMAC/Diablo is overexpressed in cancer, and demonstrated that in cancer it possesses new essential and non-apoptotic functions that are associated with regulating phospholipid synthesis including modulating mitochondrial phosphatidylserine decarboxylase activity. Here, we demonstrate additional functions for SMAC/Diablo associated with inflammation and immunity. CRISPR/Cas9 SMAC/Diablo-depleted A549 lung cancer cells displayed inhibited cell proliferation and migration. Proteomics analysis of these cells revealed altered expression of proteins associated with lipids synthesis and signaling, vesicular transport and trafficking, metabolism, epigenetics, the extracellular matrix, cell signaling, and neutrophil-mediated immunity. SMAC-KO A549 cell-showed inhibited tumor growth and proliferation and activated apoptosis. The small SMAC-depleted "tumor" showed a morphology of alveoli-like structures, reversed epithelial-mesenchymal transition, and altered tumor microenvironment. The SMAC-lacking tumor showed reduced expression of inflammation-related proteins such as NF-kB and TNF-α, and of the PD-L1, associated with immune system suppression. These results suggest that SMAC is involved in multiple processes that are essential for tumor growth and progression. Thus, targeting SMAC's non-canonical function is a potential strategy to treat cancer., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Pandey, Shteinfer-Kuzmine, Chalifa-Caspi and Shoshan-Barmatz.)
- Published
- 2022
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30. Isolation-Induced Ultrasonic Vocalization in Environmental and Genetic Mice Models of Autism.
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Shekel I, Giladi S, Raykin E, Weiner M, Chalifa-Caspi V, Lederman D, Kofman O, and Golan HM
- Abstract
Studies in rodent models suggest that calls emitted by isolated pups serve as an early behavioral manifestation of communication deficits and autistic like behavior. Previous studies in our labs showed that gestational exposure to the pesticide chlorpyrifos (CPF) and the Mthfr-knock-out mice are associated with impaired social preference and restricted or repetitive behavior. To extend these studies, we examine how pup communication via ultrasonic vocalizations is altered in these ASD models. We implemented an unsupervised hierarchical clustering method based on the spectral properties of the syllables in order to exploit syllable classification to homogeneous categories while avoiding over-categorization. Comparative exploration of the spectral and temporal aspects of syllables emitted by pups in two ASD models point to the following: (1) Most clusters showed a significant effect of the ASD factor on the start and end frequencies and bandwidth and (2) The highest percent change due to the ASD factor was on the bandwidth and duration. In addition, we found sex differences in the spectral and temporal properties of the calls in both control groups as well as an interaction between sex and the gene/environment factor. Considering the basal differences in the characteristics of syllables emitted by pups of the C57Bl/6 and Balb/c strains used as a background in the two models, we suggest that the above spectral-temporal parameters start frequency, bandwidth, and duration are the most sensitive USV features that may represent developmental changes in ASD models., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Shekel, Giladi, Raykin, Weiner, Chalifa-Caspi, Lederman, Kofman and Golan.)
- Published
- 2021
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31. CTRP6 rapidly responds to acute nutritional changes, regulating adipose tissue expansion and inflammation in mice.
- Author
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Lahav R, Haim Y, Bhandarkar NS, Levin L, Chalifa-Caspi V, Sarver D, Sahagun A, Maixner N, Kovesh B, Wong GW, and Rudich A
- Subjects
- Adipogenesis genetics, Adipokines genetics, Adipose Tissue metabolism, Animals, Cells, Cultured, Diet, High-Fat, Embryo, Mammalian, Female, HEK293 Cells, Humans, Inflammation metabolism, Inflammation pathology, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Organ Size genetics, Overnutrition genetics, Overnutrition metabolism, Overnutrition pathology, Pregnancy, Adipokines physiology, Adipose Tissue pathology, Inflammation genetics, Nutritional Physiological Phenomena genetics
- Abstract
In chronic obesity, activated adipose tissue proinflammatory cascades are tightly linked to metabolic dysfunction. Yet, close temporal analyses of the responses to obesogenic environment such as high-fat feeding (HFF) in susceptible mouse strains question the causal relationship between inflammation and metabolic dysfunction, and/or raises the possibility that certain inflammatory cascades play adaptive/homeostatic, rather than pathogenic roles. Here, we hypothesized that CTRP6, a C1QTNF family member, may constitute an early responder to acute nutritional changes in adipose tissue, with potential physiological roles. Both 3-days high-fat feeding (3dHFF) and acute obesity reversal [2-wk switch to low-fat diet after 8-wk HFF (8wHFF)] already induced marked changes in whole body fuel utilization. Although adipose tissue expression of classical proinflammatory cytokines ( Tnf-α , Ccl2 , and Il1b ) exhibited no, or only minor, change, C1qtnf6 uniquely increased, and decreased, in response to 3dHFF and acute obesity reversal, respectively. CTRP6 knockout (KO) mouse embryonic fibroblasts (MEFs) exhibited increased adipogenic gene expression ( Pparg , Fabp4 , and Adipoq ) and markedly reduced inflammatory genes ( Tnf-α , Ccl2 , and Il6 ) compared with wild-type MEFs, and recombinant CTRP6 induced the opposite gene expression signature, as assessed by RNA sequencing. Consistently, 3dHFF of CTRP6-KO mice induced a greater whole body and adipose tissue weight gain compared with wild-type littermates. Collectively, we propose CTRP6 as a gene that rapidly responds to acute changes in caloric intake, acting in acute overnutrition to induce a "physiological inflammatory response" that limits adipose tissue expansion. NEW & NOTEWORTHY CTRP6 (C1qTNF6), a member of adiponectin gene family, regulates inflammation and metabolism in established obesity. Here, short-term high-fat feeding in mice is shown to increase adipose tissue expression of CTRP6 before changes in the expression of classical inflammatory genes occur. Conversely, CTRP6 expression in adipose tissue decreases early in the course of obesity reversal. Gain- and loss-of-function models suggest CTRP6 as a positive regulator of inflammatory cascades, and a negative regulator of adipogenesis and adipose tissue expansion.
- Published
- 2021
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32. VDAC1 Silencing in Cancer Cells Leads to Metabolic Reprogramming That Modulates Tumor Microenvironment.
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Zerbib E, Arif T, Shteinfer-Kuzmine A, Chalifa-Caspi V, and Shoshan-Barmatz V
- Abstract
The tumor microenvironment (TME) plays an important role in cell growth, proliferation, migration, immunity, malignant transformation, and apoptosis. Thus, better insight into tumor-host interactions is required. Most of these processes involve the metabolic reprogramming of cells. Here, we focused on this reprogramming in cancerous cells and its effect on the TME. A major limitation in the study of tumor-host interactions is the difficulty in separating cancerous from non-cancerous signaling pathways within a tumor. Our strategy involved specifically silencing the expression of VDAC1 in the mitochondria of human-derived A549 lung cancer xenografts in mice, but not in the mouse-derived cells of the TME. Next-generation sequencing (NGS) analysis allows distinguishing the human or mouse origin of genes, thus enabling the separation of the bidirectional cross-talk between the TME and malignant cells. We demonstrate that depleting VDAC1 in cancer cells led to metabolic reprogramming, tumor regression, and the disruption of tumor-host interactions. This was reflected in the altered expression of a battery of genes associated with TME, including those involved in extracellular matrix organization and structure, matrix-related peptidases, angiogenesis, intercellular interacting proteins, integrins, and growth factors associated with stromal activities. We show that metabolic rewiring upon mitochondrial VDAC1 silencing in cancer cells affected several components of the TME, such as structural protein matrix metalloproteinases and Lox, and elicited a stromal response resembling the reaction to a foreign body in wound healing. As tumor progression requires a cooperative interplay between the host and cancer cells, and the ECM is intensively remodeled during cancer progression, VDAC1 depletion induced metabolic reprogramming that targeted both tumor cells and resulted in the alteration of the whole spectrum of TME-related genes, affecting the reciprocal feedback between ECM molecules, host cells, and cancer cells. Thus, VDAC1 depletion using si-VDAC1 represents therapeutic potential, inhibiting cancer cell proliferation and also inducing the modulation of TME components, which influences cancer progression, migration, and invasion.
- Published
- 2021
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33. BRD4 methylation by the methyltransferase SETD6 regulates selective transcription to control mRNA translation.
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Vershinin Z, Feldman M, Werner T, Weil LE, Kublanovsky M, Abaev-Schneiderman E, Sklarz M, Lam EYN, Alasad K, Picaud S, Rotblat B, McAdam RA, Chalifa-Caspi V, Bantscheff M, Chapman T, Lewis HD, Filippakopoulos P, Dawson MA, Grandi P, Prinjha RK, and Levy D
- Subjects
- Chromatin, Histone-Lysine N-Methyltransferase genetics, Histone-Lysine N-Methyltransferase metabolism, Humans, Methylation, Protein Biosynthesis, Protein Processing, Post-Translational, Cell Cycle Proteins genetics, Nuclear Proteins genetics, Nuclear Proteins metabolism, Protein Methyltransferases genetics, Transcription Factors genetics, Transcription Factors metabolism
- Abstract
The transcriptional coactivator BRD4 has a fundamental role in transcription regulation and thus became a promising epigenetic therapeutic candidate to target diverse pathologies. However, the regulation of BRD4 by posttranslational modifications has been largely unexplored. Here, we show that BRD4 is methylated on chromatin at lysine-99 by the protein lysine methyltransferase SETD6. BRD4 methylation negatively regulates the expression of genes that are involved in translation and inhibits total mRNA translation in cells. Mechanistically, we provide evidence that supports a model where BRD4 methylation by SETD6 does not have a direct role in the association with acetylated histone H4 at chromatin. However, this methylation specifically determines the recruitment of the transcription factor E2F1 to selected target genes that are involved in mRNA translation. Together, our findings reveal a previously unknown molecular mechanism for BRD4 methylation-dependent gene-specific targeting, which may serve as a new direction for the development of therapeutic applications., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)
- Published
- 2021
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34. RNA-Seq in Nonmodel Organisms.
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Chalifa-Caspi V
- Subjects
- Computational Biology methods, Gene Expression Profiling methods, Genome genetics, Molecular Sequence Annotation methods, Sequence Analysis, RNA methods, Software, Transcriptome genetics, Workflow, RNA-Seq methods
- Abstract
RNA-Seq is nowadays an indispensable approach for comparative transcriptome profiling in model and nonmodel organisms. Analyzing RNA-Seq data from nonmodel organisms poses unique challenges, due to unavailability of a high-quality genome reference and to relative sparsity of tools for downstream functional analyses. In this chapter, we provide an overview of the analysis steps in RNA-Seq projects of nonmodel organisms, while elaborating on aspects that are unique to this analysis. These will include (1) strategic decisions that have to be made in advance, regarding sequencing technology and reference to use; (2) how to search for available draft genomes, and, if necessary, how to improve their gene prediction and annotation; (3) how to clean raw reads before de novo assembly; (4) how to separate the reads in RNA-Seq projects of symbiont organisms; (5) how to design and carry out a de novo transcriptome assembly that will be comprehensive and reliable; (6) how to assess transcriptome quality; (7) when and how to reduce redundancy in the transcriptome; (8) techniques and considerations in transcriptome functional annotation; (9) quantitating transcript abundance in the face of high transcriptome redundancy; and, most importantly, (10) how to achieve functional enrichment testing using available tools which either support a large range of species or enable a universal, non-species-specific analysis.Throughout the chapter, we will refer to a variety of useful software tools. For the initial analysis steps involving high-volume data, these will include Linux-based programs. For the later steps, we will describe both Linux and R packages for advanced users, as well as many user-friendly tools for nonprogrammers. Finally, we will present a full workflow for RNA-Seq analysis of nonmodel organisms using the NeatSeq-Flow platform, which can be used locally through a user-friendly interface.
- Published
- 2021
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35. From sporadic single genes to a broader transcriptomic approach: Insights into the formation of the biomineralized exoskeleton in decapod crustaceans.
- Author
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Shaked SA, Abehsera S, Levy T, Chalifa-Caspi V, and Sagi A
- Subjects
- Animals, Chitin genetics, Epithelium physiology, Gene Expression Profiling methods, Molar physiology, Molting genetics, Proteins genetics, Animal Shells physiology, Biomineralization genetics, Crustacea genetics, Transcriptome genetics
- Abstract
One fundamental character common to pancrustaceans (Crustacea and Hexapoda) is a mineralized rigid exoskeleton whose principal organic components are chitin and proteins. In contrast to traditional research in the field that has been devoted to the structural and physicochemical aspects of biomineralization, the present study explores transcriptomic aspects of biomineralization as a first step towards adding a complementary molecular layer to this field. The rigidity of the exoskeleton in pancrustaceans dictates essential molt cycles enabling morphological changes and growth. Thus, formation and mineralization of the exoskeleton are concomitant to the timeline of the molt cycle. Skeletal proteinaceous toolkit elements have been discovered in previous studies using innovative molt-related binary gene expression patterns derived from transcriptomic libraries representing the major stages comprising the molt cycle of the decapod crustacean Cherax quadricarinatus. Here, we revisited some prominent exoskeleton-related structural proteins encoding and, using the above molt-related binary pattern methodology, enlarged the transcriptomic database of C. quadricarinatus. The latter was done by establishing a new transcriptomic library of the cuticle forming epithelium and molar tooth at four different molt stages (i.e., inter-molt, early pre-molt, late pre-molt and post-molt) and incorporating it to a previous transcriptome derived from the gastroliths and mandible. The wider multigenic approach facilitated by the newly expanded transcriptomic database not only revisited single genes of the molecular toolkit, but also provided both scattered and specific information that broaden the overview of proteins and gene clusters which are involved in the construction and biomineralization of the exoskeleton in decapod crustaceans., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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36. A TRAIL-TL1A Paracrine Network Involving Adipocytes, Macrophages, and Lymphocytes Induces Adipose Tissue Dysfunction Downstream of E2F1 in Human Obesity.
- Author
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Maixner N, Pecht T, Haim Y, Chalifa-Caspi V, Goldstein N, Tarnovscki T, Liberty IF, Kirshtein B, Golan R, Berner O, Monsonego A, Bashan N, Blüher M, and Rudich A
- Subjects
- Adipose Tissue physiology, Adolescent, Adult, Aged, Aged, 80 and over, Cells, Cultured, Coculture Techniques, E2F1 Transcription Factor genetics, Female, Gene Expression Regulation, Humans, Male, Middle Aged, Paracrine Communication, TNF-Related Apoptosis-Inducing Ligand genetics, Tumor Necrosis Factor Ligand Superfamily Member 15 genetics, Young Adult, Adipocytes physiology, E2F1 Transcription Factor metabolism, Lymphocytes physiology, Macrophages physiology, TNF-Related Apoptosis-Inducing Ligand metabolism, Tumor Necrosis Factor Ligand Superfamily Member 15 metabolism
- Abstract
Elevated expression of E2F1 in adipocyte fraction of human visceral adipose tissue (hVAT) associates with a poor cardiometabolic profile. We hypothesized that beyond directly activating autophagy and MAP3K5 (ASK)-MAP kinase signaling, E2F1 governs a distinct transcriptome that contributes to adipose tissue and metabolic dysfunction in obesity. We performed RNA sequencing of hVAT samples from age-, sex-, and BMI-matched patients, all obese, whose visceral E2F1 protein expression was either high (E2F1
high ) or low (E2F1low ). Tumor necrosis factor superfamily (TNFSF) members, including TRAIL ( TNFSF10 ), TL1A ( TNFSF15 ), and their receptors, were enriched in E2F1high While TRAIL was equally expressed in adipocytes and stromal vascular fraction (SVF), TL1A was mainly expressed in SVF, and TRAIL-induced TL1A was attributed to CD4+ and CD8+ subclasses of hVAT T cells. In human adipocytes, TL1A enhanced basal and impaired insulin-inhibitable lipolysis and altered adipokine secretion, and in human macrophages it induced foam cell biogenesis and M1 polarization. Two independent human cohorts confirmed associations between TL1A and TRAIL expression in hVAT and higher leptin and IL6 serum concentrations, diabetes status, and hVAT-macrophage lipid content. Jointly, we propose an intra-adipose tissue E2F1-associated TNFSF paracrine loop engaging lymphocytes, macrophages, and adipocytes, ultimately contributing to adipose tissue dysfunction in obesity., (© 2020 by the American Diabetes Association.)- Published
- 2020
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37. Two Homogametic Genotypes - One Crayfish: On the Consequences of Intersexuality.
- Author
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Levy T, Ventura T, De Leo G, Grinshpan N, Abu Abayed FA, Manor R, Savaya A, Sklarz MY, Chalifa-Caspi V, Mishmar D, and Sagi A
- Abstract
In the Australian redclaw crayfish, Cherax quadricarinatus (WZ/ZZ system), intersexuals, although exhibiting both male and female gonopores, are functional males bearing a female genotype (WZ males). Therefore, the occurrence of the unusual homogametic WW females in nature is plausible. We developed W/Z genomic sex markers and used them to investigate the genotypic structure of experimental and native C. quadricarinatus populations in Australia. We discovered, for the first time, the natural occurrence of WW females in crustacean populations. By modeling population dynamics, we found that intersexuals contribute to the growth rate of crayfish populations in the short term. Given the vastly fragmented C. quadricarinatus habitat, which is characterized by drought-flood cycles, we speculate that intersexuals contribute to the fitness of this species since they lead to occasional increment in the population growth rate which potentially supports crayfish population restoration and establishment under extinction threats or colonization events., Competing Interests: A patent regarding sex-specific genomic markers in the Australian redclaw crayfish is pending (International application number: PCT/IL2018/051046, International publication number: WO/2019/058371)., (© 2020 The Authors.)
- Published
- 2020
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38. Differential network analysis of multiple human tissue interactomes highlights tissue-selective processes and genetic disorder genes.
- Author
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Basha O, Argov CM, Artzy R, Zoabi Y, Hekselman I, Alfandari L, Chalifa-Caspi V, and Yeger-Lotem E
- Subjects
- Gene Ontology, Gene Regulatory Networks, Humans, Biological Phenomena, Protein Interaction Maps
- Abstract
Motivation: Differential network analysis, designed to highlight network changes between conditions, is an important paradigm in network biology. However, differential network analysis methods have been typically designed to compare between two conditions and were rarely applied to multiple protein interaction networks (interactomes). Importantly, large-scale benchmarks for their evaluation have been lacking., Results: Here, we present a framework for assessing the ability of differential network analysis of multiple human tissue interactomes to highlight tissue-selective processes and disorders. For this, we created a benchmark of 6499 curated tissue-specific Gene Ontology biological processes. We applied five methods, including four differential network analysis methods, to construct weighted interactomes for 34 tissues. Rigorous assessment of this benchmark revealed that differential analysis methods perform well in revealing tissue-selective processes (AUCs of 0.82-0.9). Next, we applied differential network analysis to illuminate the genes underlying tissue-selective hereditary disorders. For this, we curated a dataset of 1305 tissue-specific hereditary disorders and their manifesting tissues. Focusing on subnetworks containing the top 1% differential interactions in disease-relevant tissue interactomes revealed significant enrichment for disorder-causing genes in 18.6% of the cases, with a significantly high success rate for blood, nerve, muscle and heart diseases., Summary: Altogether, we offer a framework that includes expansive manually curated datasets of tissue-selective processes and disorders to be used as benchmarks or to illuminate tissue-selective processes and genes. Our results demonstrate that differential analysis of multiple human tissue interactomes is a powerful tool for highlighting processes and genes with tissue-selective functionality and clinical impact., Availability and Implementation: Datasets are available as part of the Supplementary data., Supplementary Information: Supplementary data are available at Bioinformatics online., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2020
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39. The Mitochondrial Protein VDAC1 at the Crossroads of Cancer Cell Metabolism: The Epigenetic Link.
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Amsalem Z, Arif T, Shteinfer-Kuzmine A, Chalifa-Caspi V, and Shoshan-Barmatz V
- Abstract
Carcinogenesis is a complicated process that involves the deregulation of epigenetics, resulting in cellular transformational events, such as proliferation, differentiation, and metastasis. Most chromatin-modifying enzymes utilize metabolites as co-factors or substrates and thus are directly dependent on such metabolites as acetyl-coenzyme A, S-adenosylmethionine, and NAD+. Here, we show that using specific siRNA to deplete a tumor of VDAC1 not only led to reprograming of the cancer cell metabolism but also altered several epigenetic-related enzymes and factors. VDAC1, in the outer mitochondrial membrane, controls metabolic cross-talk between the mitochondria and the rest of the cell, thus regulating the metabolic and energetic functions of mitochondria, and has been implicated in apoptotic-relevant events. We previously demonstrated that silencing VDAC1 expression in glioblastoma (GBM) U-87MG cell-derived tumors, resulted in reprogramed metabolism leading to inhibited tumor growth, angiogenesis, epithelial-mesenchymal transition and invasiveness, and elimination of cancer stem cells, while promoting the differentiation of residual tumor cells into neuronal-like cells. These VDAC1 depletion-mediated effects involved alterations in transcription factors regulating signaling pathways associated with cancer hallmarks. As the epigenome is sensitive to cellular metabolism, this study was designed to assess whether depleting VDAC1 affects the metabolism-epigenetics axis. Using DNA microarrays, q-PCR, and specific antibodies, we analyzed the effects of si-VDAC1 treatment of U-87MG-derived tumors on histone modifications and epigenetic-related enzyme expression levels, as well as the methylation and acetylation state, to uncover any alterations in epigenetic properties. Our results demonstrate that metabolic rewiring of GBM via VDAC1 depletion affects epigenetic modifications, and strongly support the presence of an interplay between metabolism and epigenetics.
- Published
- 2020
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40. Rewiring of Cancer Cell Metabolism by Mitochondrial VDAC1 Depletion Results in Time-Dependent Tumor Reprogramming: Glioblastoma as a Proof of Concept.
- Author
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Arif T, Stern O, Pittala S, Chalifa-Caspi V, and Shoshan-Barmatz V
- Subjects
- Animals, Apoptosis drug effects, Cell Differentiation drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Cellular Reprogramming physiology, Humans, Male, Mice, Mice, Nude, Mitochondria metabolism, Neoplastic Stem Cells pathology, Proof of Concept Study, RNA, Small Interfering metabolism, Receptors, GABA metabolism, Signal Transduction, Voltage-Dependent Anion Channel 1 physiology, Glioblastoma metabolism, Voltage-Dependent Anion Channel 1 metabolism
- Abstract
Reprograming of the metabolism of cancer cells is an event recognized as a hallmark of the disease. The mitochondrial gatekeeper, voltage-dependent anion channel 1 (VDAC1), mediates transport of metabolites and ions in and out of mitochondria, and is involved in mitochondria-mediated apoptosis. Here, we compared the effects of reducing hVDAC1 expression in a glioblastoma xenograft using human-specific si-RNA (si-hVDAC1) for a short (19 days) and a long term (40 days). Tumors underwent reprograming, reflected in rewired metabolism, eradication of cancer stem cells (CSCs) and differentiation. Short- and long-term treatments of the tumors with si-hVDAC1 similarly reduced the expression of metabolism-related enzymes, and translocator protein (TSPO) and CSCs markers. In contrast, differentiation into cells expressing astrocyte or neuronal markers was noted only after a long period during which the tumor cells were hVDAC1-depleted. This suggests that tumor cell differentiation is a prolonged process that precedes metabolic reprograming and the "disappearance" of CSCs. Tumor proteomics analysis revealing global changes in the expression levels of proteins associated with signaling, synthesis and degradation of proteins, DNA structure and replication and epigenetic changes, all of which were highly altered after a long period of si-hVDAC1 tumor treatment. The depletion of hVDAC1 greatly reduced the levels of the multifunctional translocator protein TSPO, which is overexpressed in both the mitochondria and the nucleus of the tumor. The results thus show that VDAC1 depletion-mediated cancer cell metabolic reprograming involves a chain of events occurring in a sequential manner leading to a reversal of the unique properties of the tumor, indicative of the interplay between metabolism and oncogenic signaling networks., Competing Interests: The authors declare no conflict of interest.
- Published
- 2019
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41. Rapid Atrial Pacing Promotes Atrial Fibrillation Substrate in Unanesthetized Instrumented Rats.
- Author
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Mulla W, Hajaj B, Elyagon S, Mor M, Gillis R, Murninkas M, Klapper-Goldstein H, Plaschkes I, Chalifa-Caspi V, Etzion S, and Etzion Y
- Abstract
Aim: The self-perpetuating nature of atrial fibrillation (AF) has been a subject of intense research in large mammalian models exposed to rapid atrial pacing (RAP). Recently, rodents are increasingly used to gain insight into the pathophysiology of AF. However, little is known regarding the effects of RAP on the atria of rats and mice. Using an implantable device for electrophysiological studies in rodents, we examined on a daily basis, the effects of continuous RAP on the developed AF substrate of unanesthetized rats and mice., Methods and Results: Aggressive burst pacing did not induce AF at baseline in the large majority of rodents, but repeatedly induced AF episodes in rats exposed to RAP for more than 2 days. A microarray study of left atrial tissue from rats exposed to RAP for 2 days vs. control pacing identified 304 differentially expressed genes. Enrichment analysis and comparison with a dataset of atrial tissue from AF patients revealed indications of increased carbohydrate metabolism and changes in pathways that are thought to play critical roles in human AF, including TGF-beta and IL-6 signaling. Among 19 commonly affected genes in comparison with human AF, downregulation of FOXP1 and upregulation of the KCNK2 gene encoding the Kir2.1 potassium channel were conspicuous findings, suggesting NFAT activation. Further results included reduced expression of MIR-26 and MIR-101, which is in line with NFAT activation., Conclusion: Our results demonstrate electrophysiological evidence for AF promoting effects of RAP in rats and several molecular similarities between the effects of RAP in large and small mammalian models., (Copyright © 2019 Mulla, Hajaj, Elyagon, Mor, Gillis, Murninkas, Klapper-Goldstein, Plaschkes, Chalifa-Caspi, Etzion and Etzion.)
- Published
- 2019
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42. Production of WW males lacking the masculine Z chromosome and mining the Macrobrachium rosenbergii genome for sex-chromosomes.
- Author
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Levy T, Rosen O, Manor R, Dotan S, Azulay D, Abramov A, Sklarz MY, Chalifa-Caspi V, Baruch K, Shechter A, and Sagi A
- Subjects
- Animals, Female, Genome, Genotype, Larva genetics, Male, Palaemonidae growth & development, Phenotype, Sex Determination Analysis, Sex Differentiation, Palaemonidae genetics, Sex Chromosomes
- Abstract
The cultivation of monosex populations is common in animal husbandry. However, preselecting the desired gender remains a major biotechnological and ethical challenge. To achieve an efficient biotechnology for all-female aquaculture in the economically important prawn (Macrobrachium rosenbergii), we achieved - for the first time - WW males using androgenic gland cells transplantation which caused full sex-reversal of WW females to functional males. Crossing the WW males with WW females yielded all-female progeny lacking the Z chromosome. We now have the ability to manipulate - by non-genomic means - all possible genotype combinations (ZZ, WZ and WW) to retain either male or female phenotypes and hence to produce monosex populations of either gender. This calls for a study of the genomic basis underlying this striking sexual plasticity, questioning the content of the W and Z chromosomes. Here, we report on the sequencing of a high-quality genome exhibiting distinguishable paternal and maternal sequences. This assembly covers ~ 87.5% of the genome and yielded a remarkable N50 value of ~ 20 × 10
6 bp. Genomic sex markers were used to initiate the identification and validation of parts of the W and Z chromosomes for the first time in arthropods.- Published
- 2019
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43. Aging promotes reorganization of the CD4 T cell landscape toward extreme regulatory and effector phenotypes.
- Author
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Elyahu Y, Hekselman I, Eizenberg-Magar I, Berner O, Strominger I, Schiller M, Mittal K, Nemirovsky A, Eremenko E, Vital A, Simonovsky E, Chalifa-Caspi V, Friedman N, Yeger-Lotem E, and Monsonego A
- Subjects
- Animals, High-Throughput Nucleotide Sequencing, Mice, Sequence Analysis, RNA, Single-Cell Analysis, T-Lymphocyte Subsets immunology, T-Lymphocyte Subsets metabolism, Aging immunology, Aging metabolism, CD4-Positive T-Lymphocytes immunology, CD4-Positive T-Lymphocytes metabolism, Immunomodulation, Phenotype
- Abstract
Age-associated changes in CD4 T-cell functionality have been linked to chronic inflammation and decreased immunity. However, a detailed characterization of CD4 T cell phenotypes that could explain these dysregulated functional properties is lacking. We used single-cell RNA sequencing and multidimensional protein analyses to profile thousands of CD4 T cells obtained from young and old mice. We found that the landscape of CD4 T cell subsets differs markedly between young and old mice, such that three cell subsets-exhausted, cytotoxic, and activated regulatory T cells (aT
regs )-appear rarely in young mice but gradually accumulate with age. Most unexpected were the extreme pro- and anti-inflammatory phenotypes of cytotoxic CD4 T cells and aTregs , respectively. These findings provide a comprehensive view of the dynamic reorganization of the CD4 T cell milieu with age and illuminate dominant subsets associated with chronic inflammation and immunity decline, suggesting new therapeutic avenues for age-related diseases.- Published
- 2019
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- View/download PDF
44. Metabolomics reveals novel insight on dormancy of aquatic invertebrate encysted embryos.
- Author
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Rozema E, Kierszniowska S, Almog-Gabai O, Wilson EG, Choi YH, Verpoorte R, Hamo R, Chalifa-Caspi V, Assaraf YG, and Lubzens E
- Subjects
- Animals, Embryo, Nonmammalian, Hydrobiology, Invertebrates embryology, Metabolomics
- Abstract
Numerous aquatic invertebrates survive harsh environments by displaying dormancy as encysted embryos. This study aimed at determining whether metabolomics could provide molecular insight to explain the "dormancy syndrome" by highlighting functional pathways and metabolites, hence offering a novel comprehensive molecular view of dormancy. We compared the metabolome of morphologically distinct dormant encysted embryos (resting eggs) and non-dormant embryos (amictic eggs) of a rotifer (Brachionus plicatilis). Metabolome profiling revealed ~5,000 features, 1,079 of which were annotated. Most of the features were represented at significantly higher levels in non-dormant than dormant embryos. A large number of features was assigned to putative functional pathways indicating novel differences between dormant and non-dormant states. These include features associated with glycolysis, the TCA and urea cycles, amino acid, purine and pyrimidine metabolism. Interestingly, ATP, nucleobases, cyclic nucleotides, thymidine and uracil, were not detected in dormant resting eggs, suggesting an impairment of response to environmental and internal cues, cessation of DNA synthesis, transcription and plausibly translation in the dormant embryos. The levels of trehalose or its analogues, with a role in survival under desiccation conditions, were higher in resting eggs. In conclusion, the current study highlights metabolomics as a major analytical tool to functionally compare dormancy across species.
- Published
- 2019
- Full Text
- View/download PDF
45. CSBFinder: discovery of colinear syntenic blocks across thousands of prokaryotic genomes.
- Author
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Svetlitsky D, Dagan T, Chalifa-Caspi V, and Ziv-Ukelson M
- Subjects
- Algorithms, Genome, Microbial, Synteny, Genomics, Software
- Abstract
Motivation: Identification of conserved syntenic blocks across microbial genomes is important for several problems in comparative genomics such as gene annotation, study of genome organization and evolution and prediction of gene interactions. Current tools for syntenic block discovery do not scale up to the large quantity of prokaryotic genomes available today., Results: We present a novel methodology for the discovery, ranking and taxonomic distribution analysis of colinear syntenic blocks (CSBs)-groups of genes that are consistently located close to each other, in the same order, across a wide range of taxa. We present an efficient algorithm that identifies CSBs in large genomic datasets. The algorithm is implemented and incorporated in a novel tool with a graphical user interface, denoted CSBFinder, that ranks the discovered CSBs according to a probabilistic score and clusters them to families according to their gene content similarity. We apply CSBFinder to data mine 1487 prokaryotic genomes including chromosomes and plasmids. For post-processing analysis, we generate heatmaps for visualizing the distribution of CSB family members across various taxa. We exemplify the utility of CSBFinder in operon prediction, in deciphering unknown gene function and in taxonomic analysis of colinear syntenic blocks., Availability and Implementation: CSBFinder software and code are publicly available at https://github.com/dinasv/CSBFinder., Supplementary Information: Supplementary data are available at Bioinformatics online., (© The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2019
- Full Text
- View/download PDF
46. Synergistic effects of abiotic stresses in plants: a case study of nitrogen limitation and saturating light intensity in Arabidopsis thaliana.
- Author
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Cohen I, Rapaport T, Chalifa-Caspi V, and Rachmilevitch S
- Subjects
- Anthocyanins metabolism, Carbon metabolism, Chlorophyll metabolism, Chloroplasts metabolism, Stress, Physiological radiation effects, Arabidopsis metabolism, Arabidopsis radiation effects, Arabidopsis Proteins metabolism, Light, Nitrogen metabolism
- Abstract
Under natural conditions, plants are regularly exposed to combinations of stress factors. A common example is the conjunction between nitrogen (N) deficiency and excess light. The combined effect of stress factors is often ignored in studies using controlled conditions, possibly resulting in misleading conclusions. To address this issue, the present study examined the physiological behavior of Arabidopsis thaliana under the effect of varying nitrogen levels and light intensities. The joint influence of low N and excess light had an adverse effect on plant growth, chlorophyll and anthocyanin concentrations, photochemical capacity and the abundance of proteins involved in carbon assimilation and antioxidative metabolism. In contrast, no adverse physiological responses were observed for plants under either nitrogen limitation or high light (HL) intensity conditions (i.e. single stress). The underlying mechanisms for the increased growth in conditions of HL and sufficient nitrogen were a combination of chlorophyll accumulation and an increased number of proteins involved in C3 carbon assimilation, amino acids biosynthesis and chloroplast development. In contrast, combined stress conditions shifts plants from growth to survival by displaying anthocyanin accumulation and an increased number of proteins involved in catabolism of lipids and amino acids as energy substrates. Ultimately switching plants development from growth to survival. Our results suggest that an assessment of the physiological response to the combined effect of multiple stresses cannot be directly extrapolated from the physiological response to a single stress. Specifically, the synergistic interaction between N deficiency and saturating light in Arabidopsis plants could not have been modeled via only one of the stress factors., (© 2018 Scandinavian Plant Physiology Society.)
- Published
- 2019
- Full Text
- View/download PDF
47. Streptococcus pneumoniae Cell Wall-Localized Trigger Factor Elicits a Protective Immune Response and Contributes to Bacterial Adhesion to the Host.
- Author
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Cohen A, Troib S, Dotan S, Najmuldeen H, Yesilkaya H, Kushnir T, Shagan M, Portnoi M, Nachmani H, Benisty R, Tal M, Ellis R, Chalifa-Caspi V, Dagan R, and Nebenzahl YM
- Subjects
- Animals, Bacterial Adhesion immunology, Bacterial Adhesion physiology, Computational Biology, Female, Flow Cytometry, Immunoblotting, Mice, Mice, Inbred BALB C, Peptidylprolyl Isomerase immunology, Peptidylprolyl Isomerase metabolism, Streptococcus pneumoniae immunology, Virulence, Cell Wall immunology, Cell Wall metabolism, Streptococcus pneumoniae metabolism, Streptococcus pneumoniae pathogenicity
- Abstract
Trigger factor (TF) has a known cytoplasmic function as a chaperone. In a previous study we showed that pneumococcal TF is also cell-wall localized and this finding combined with the immunogenic characteristic of TF, has led us to determine the vaccine potential of TF and decipher its involvement in pneumococcal pathogenesis. Bioinformatic analysis revealed that TF is conserved among pneumococci and has no human homologue. Immunization of mice with recombinant (r)TF elicited a protective immune response against a pneumococcal challenge, suggesting that TF contributes to pneumococcal pathogenesis. Indeed, rTF and an anti-rTF antiserum inhibited bacterial adhesion to human lung derived epithelial cells, indicating that TF contributes to the bacterial adhesion to the host. Moreover, bacteria lacking TF demonstrated reduced adhesion, in vitro, to lung-derived epithelial cells, neural cells and glial cells. The reduced adhesion could be restored by chromosomal complementation. Furthermore, bacteria lacking TF demonstrated significantly reduced virulence in a mouse model. Taken together, the ability of rTF to elicit a protective immune response, involvement of TF in bacterial adhesion, conservation of the protein among pneumococcal strains and the lack of human homologue, all suggest that rTF can be considered as a future candidate vaccine with a much broader coverage as compared to the currently available pneumococcal vaccines.
- Published
- 2019
- Full Text
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48. Molecular Mode of Action of Asteriscus graveolens as an Anticancer Agent.
- Author
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Tayeh Z, Dudai N, Schechter A, Chalifa-Caspi V, Barak S, and Ofir R
- Subjects
- Animals, Antineoplastic Agents administration & dosage, Antineoplastic Agents chemistry, Apoptosis drug effects, Caspase 3 metabolism, Cell Line, Tumor, Cell Survival drug effects, Dose-Response Relationship, Drug, Humans, Mice, Plant Extracts administration & dosage, Plant Extracts chemistry, Plant Extracts pharmacology, Plant Leaves chemistry, Reactive Oxygen Species metabolism, Sesquiterpenes administration & dosage, Sesquiterpenes chemistry, Sesquiterpenes pharmacology, Transcriptome, Antineoplastic Agents pharmacology, Asteraceae chemistry, DNA Fragmentation drug effects, Gene Expression Regulation drug effects, Induced Pluripotent Stem Cells drug effects
- Abstract
Asteriscus graveolens ( A. graveolens ) plants contain among other metabolites, sesquiterpene lactone asteriscunolide isomers (AS). The crude extract and its fractions affected the viability of mouse BS-24-1 lymphoma cells (BS-24-1 cells) with an IC50 of 3 μg/mL. The fraction was cytotoxic to cancer cells but not to non-cancerous cells (human induced pluripotent stem cells); its activity was accompanied by a concentration- and time-dependent appearance of apoptosis as determined by DNA fragmentation and caspase-3 activity. High levels of Reactive Oxygen Species (ROS) were rapidly observed (less than 1 min) after addition of the fraction followed by an increase in caspase-3 activity three hours later. Comparison of RNA-seq transcriptome profiles from pre-and post-treatment of BS-24-1 cells with crude extract of A. graveolens yielded a list of 2293 genes whose expression was significantly affected. This gene set included genes encoding proteins involved in cell cycle arrest, protection against ROS, and activation of the tumor suppressor P53 pathway, supporting the biochemical findings on ROS species-dependent apoptosis induced by A. graveolens fraction. Interestingly, several of the pathways and genes affected by A. graveolens extract are expressed following treatment of human cancer cells with chemotherapy drugs. We suggest, that A. graveolens extracts maybe further developed into selective chemotherapy.
- Published
- 2018
- Full Text
- View/download PDF
49. A Biclique Approach to Reference-Anchored Gene Blocks and Its Applications to Genomic Islands.
- Author
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Benshahar A, Chalifa-Caspi V, Hermelin D, and Ziv-Ukelson M
- Subjects
- Algorithms, Contig Mapping methods, Contig Mapping standards, Reference Standards, Sequence Analysis, DNA standards, Genome, Bacterial, Multigene Family, Sequence Analysis, DNA methods
- Abstract
We formalize a new problem variant in gene-block discovery, denoted Reference-Anchored Gene Blocks (RAGB), given a query sequence Q of length n, representing the gene array of a DNA element, a window size bound d on the length of a substring of interest in Q, and a set of target gene sequences [Formula: see text]. Our objective is to identify gene blocks in [Formula: see text] that are centered in a subset q of co-localized genes from Q, and contain genomes from [Formula: see text] in which the corresponding orthologs of the genes from q are also co-localized. We cast RAGB as a variant of a (colored) biclique problem in bipartite graphs, and analyze its parameterized complexity, as well as the parameterized complexity of other related problems. We give an [Formula: see text] time algorithm for the uncolored variant of our biclique problem, where m is the number of areas of interest that are parsed from the target sequences, and n and d are as defined earlier. Our algorithm can be adapted to compute all maximal bicliques in the graph within the same time complexity, and to handle edge weights with a slight [Formula: see text] increase to its time complexity. For the colored version of the problem, our algorithm has a time complexity of [Formula: see text]. We implement the algorithm and exemplify its application to the data mining of proteobacterial gene blocks that are centered in predicted proteobacterial genomic islands, leading to the identification of putatively mobilized clusters of virulence, pathogenicity, and resistance genes.
- Published
- 2018
- Full Text
- View/download PDF
50. Flavin Reductase Contributes to Pneumococcal Virulence by Protecting from Oxidative Stress and Mediating Adhesion and Elicits Protection Against Pneumococcal Challenge.
- Author
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Morozov GI, Porat N, Kushnir T, Najmuldeen H, Adawi A, Chalifa-Caspi V, Benisty R, Ohayon A, Liron O, Azriel S, Malka I, Dotan S, Portnoi M, Piotrowski AA, Kafka D, Hajaj B, Fishilevich T, Shagan M, Tal M, Ellis R, Morrison DA, Mitchell AM, Mitchell TJ, Dagan R, Yesilkaya H, and Nebenzahl YM
- Subjects
- Animals, Bacterial Proteins metabolism, Cell Line, Tumor, Cells, Cultured, FMN Reductase metabolism, Female, Humans, Macrophages, Peritoneal microbiology, Mice, Mice, Inbred BALB C, Mice, Inbred CBA, Mutation, Phagocytosis, Streptococcus pneumoniae enzymology, Streptococcus pneumoniae genetics, Virulence genetics, Bacterial Adhesion, Bacterial Proteins genetics, FMN Reductase genetics, Oxidative Stress, Streptococcus pneumoniae pathogenicity
- Abstract
Pneumococcal flavin reductase (FlaR) is known to be cell-wall associated and possess age dependent antigenicity in children. This study aimed at characterizing FlaR and elucidating its involvement in pneumococcal physiology and virulence. Bioinformatic analysis of FlaR sequence identified three-conserved cysteine residues, suggesting a transition metal-binding capacity. Recombinant FlaR (rFlaR) bound Fe
2+ and exhibited FAD-dependent NADP-reductase activity, which increased in the presence of cysteine or excess Fe2+ and inhibited by divalent-chelating agents. flaR mutant was highly susceptible to H2 O2 compared to its wild type (WT) and complemented strains, suggesting a role for FlaR in pneumococcal oxidative stress resistance. Additionally, flaR mutant demonstrated significantly decreased mice mortality following intraperitoneal infection. Interestingly, lack of FlaR did not affect the extent of phagocytosis by primary mouse peritoneal macrophages but reduced adhesion to A549 cells compared to the WT and complemented strains. Noteworthy are the findings that immunization with rFlaR elicited protection in mice against intraperitoneal lethal challenge and anti-FlaR antisera neutralized bacterial virulence. Taken together, FlaR's roles in pneumococcal physiology and virulence, combined with its lack of significant homology to human proteins, point towards rFlaR as a vaccine candidate.- Published
- 2018
- Full Text
- View/download PDF
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