42 results on '"Suppressor"'
Search Results
2. Semaphorin-3F/Neuropilin-2 Transcriptional Expression as a Predictive Biomarker of Occult Lymph Node Metastases in HNSCC
- Author
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Universitat Rovira i Virgili, Meler-Claramonte C; Avilés-Jurado FX; Vilaseca I; Terra X; Bragado P; Fuster G; Vintró XL; Camacho M, Universitat Rovira i Virgili, and Meler-Claramonte C; Avilés-Jurado FX; Vilaseca I; Terra X; Bragado P; Fuster G; Vintró XL; Camacho M
- Abstract
The expression of the semaphorin-3F (SEMA3F) and neuropilin-2 (NRP2) is involved in the regulation of lymphangiogenesis. The present study analyzes the relationship between the transcriptional expression of the SEMA3F-NRP2 genes and the presence of occult lymph node metastases in patients with cN0 head and neck squamous cell carcinomas. We analyzed the transcriptional expression of SEMA3F and NRP2 in a cohort of 53 patients with cN0 squamous cell carcinoma treated with an elective neck dissection. Occult lymph node metastases were found in 37.7% of the patients. Patients with occult lymph node metastases (cN0/pN+) had significantly lower SEMA3F expression values than patients without lymph node involvement (cN0/pN0). Considering the expression of the SEMA3F-NRP2 genes, patients were classified into two groups according to the risk of occult nodal metastasis: Group 1 (n = 34), high SEMA3F/low NRP2 expression, with a low risk of occult nodal involvement (14.7% cN0/pN+); Group 2 (n = 19), low SEMA3F or high SEMA3F/high NRP2 expression, with a high risk of occult nodal involvement (78.9% cN0/pN+). Multivariate analysis showed that patients in Group 2 had a 26.2 higher risk of lymph node involvement than patients in Group 1. There was a significant relationship between the transcriptional expression values of the SEMA3F-NRP2 genes and the risk of occult nodal metastases.
- Published
- 2022
3. RCB initiates Arabidopsis thermomorphogenesis by stabilizing the thermoregulator PIF4 in the daytime.
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Qiu, Yongjian, Qiu, Yongjian, Pasoreck, Elise K, Yoo, Chan Yul, He, Jiangman, Wang, He, Bajracharya, Abhishesh, Li, Meina, Larsen, Haley D, Cheung, Stacey, Chen, Meng, Qiu, Yongjian, Qiu, Yongjian, Pasoreck, Elise K, Yoo, Chan Yul, He, Jiangman, Wang, He, Bajracharya, Abhishesh, Li, Meina, Larsen, Haley D, Cheung, Stacey, and Chen, Meng
- Abstract
Daytime warm temperature elicits thermomorphogenesis in Arabidopsis by stabilizing the central thermoregulator PHYTOCHROME INTERACTING transcription FACTOR 4 (PIF4), whose degradation is otherwise promoted by the photoreceptor and thermosensor phytochrome B. PIF4 stabilization in the light requires a transcriptional activator, HEMERA (HMR), and is abrogated when HMR's transactivation activity is impaired in hmr-22. Here, we report the identification of a hmr-22 suppressor mutant, rcb-101, which surprisingly carries an A275V mutation in REGULATOR OF CHLOROPLAST BIOGENESIS (RCB). rcb-101/hmr-22 restores thermoresponsive PIF4 accumulation and reverts the defects of hmr-22 in chloroplast biogenesis and photomorphogenesis. Strikingly, similar to hmr, the null rcb-10 mutant impedes PIF4 accumulation and thereby loses the warm-temperature response. rcb-101 rescues hmr-22 in an allele-specific manner. Consistently, RCB interacts directly with HMR. Together, these results unveil RCB as a novel temperature signaling component that functions collaboratively with HMR to initiate thermomorphogenesis by selectively stabilizing PIF4 in the daytime.
- Published
- 2021
4. Disentangling the effects of intrapersonal and interpersonal emotional competence on parental burnout
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UCL - SSH/IPSY - Psychological Sciences Research Institute, Lin, Gao-Xian, Roskam, Isabelle, Mikolajczak, Moïra, UCL - SSH/IPSY - Psychological Sciences Research Institute, Lin, Gao-Xian, Roskam, Isabelle, and Mikolajczak, Moïra
- Abstract
Emotional competence (EC) has been documented as one of the most influential resource to protect parents from parental burnout (PB). However, the dimensions of EC have inconsistent effects across studies: while intrapersonal EC consistently had a protective effect on PB, interpersonal EC was paradoxically documented both as a risk factor and a protective factor. Relying on third-variable effect analyses on two independent datasets (842 Belgian parents and 377 Polish parents), this pre-registered study found that (1) intrapersonal EC drives the protective effect of interpersonal EC, and (2) after being adjusted for intrapersonal EC, interpersonal EC does not have significant effect on PB in the Polish sample and even becomes detrimental in the Belgian sample. These findings highlight the importance of examining the unique effect of each EC dimension while controlling for the others. Besides, it also implicates interventions aimed at improving EC to reduce PB should focus on intrapersonal EC.
- Published
- 2021
5. MULTI-DRONE COLLABORATION FOR SEARCH AND RESCUE MISSIONS
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Forsslund, Patrik, Monié, Simon, Forsslund, Patrik, and Monié, Simon
- Abstract
Unmanned Aerial Vehicle (UAV), also called drones, are used for Search And Rescue (SAR) missions, mainly in the form of a pilot manoeuvring a single drone. However, the increase in labour to cover larger areas quickly would result in a very high cost and time spent per rescue operation. Therefore, there is a need for an easy to use, low-cost, and highly autonomous swarm of drones for SAR missions where the detection and rescue times are kept to a minimum. In this thesis, a Subsumption-based architecture is proposed, which combines multiple behaviours to create more complex behaviours. An investigation of (1) what are the critical aspects of controlling a swarm of drones, (2) how can a combination of different behavioural algorithms increase the performance of a swarm of drones, and (3) what benchmarks are necessary when evaluating the fitness of the behavioural algorithms. The proposed architecture was simulated in AirSim using the SimpleFlight flight controller through experiments that evaluated the individual layers and missions that simulated real-life scenarios. The results validate the modularity and reliability of the architecture, where the architecture has the potential for improvements in future iterations. For the search area of 400×400meters, the swarm consistently produced an average area coverage of at least 99.917% and found all the missing people in all missions, with the slowest average being 563 seconds. Compared to related work, the result produced similar or better times when scaled to the same proportions and higher area coverage. As comparisons of results in SAR missions can be difficult, the introduction of Active time can serve as a benchmark for others in future swarm performance measurements.
- Published
- 2021
6. The characterization of Mediator 12 and 13 as conditional positive gene regulators in Arabidopsis.
- Author
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Liu, Qikun, Liu, Qikun, Bischof, Sylvain, Harris, C Jake, Zhong, Zhenhui, Zhan, Lingyu, Nguyen, Calvin, Rashoff, Andrew, Barshop, William D, Sun, Fei, Feng, Suhua, Potok, Magdalena, Gallego-Bartolome, Javier, Zhai, Jixian, Wohlschlegel, James A, Carey, Michael F, Long, Jeffrey A, Jacobsen, Steven E, Liu, Qikun, Liu, Qikun, Bischof, Sylvain, Harris, C Jake, Zhong, Zhenhui, Zhan, Lingyu, Nguyen, Calvin, Rashoff, Andrew, Barshop, William D, Sun, Fei, Feng, Suhua, Potok, Magdalena, Gallego-Bartolome, Javier, Zhai, Jixian, Wohlschlegel, James A, Carey, Michael F, Long, Jeffrey A, and Jacobsen, Steven E
- Abstract
Mediator 12 (MED12) and MED13 are components of the Mediator multi-protein complex, that facilitates the initial steps of gene transcription. Here, in an Arabidopsis mutant screen, we identify MED12 and MED13 as positive gene regulators, both of which contribute broadly to morc1 de-repressed gene expression. Both MED12 and MED13 are preferentially required for the expression of genes depleted in active chromatin marks, a chromatin signature shared with morc1 re-activated loci. We further discover that MED12 tends to interact with genes that are responsive to environmental stimuli, including light and radiation. We demonstrate that light-induced transient gene expression depends on MED12, and is accompanied by a concomitant increase in MED12 enrichment during induction. In contrast, the steady-state expression level of these genes show little dependence on MED12, suggesting that MED12 is primarily required to aid the expression of genes in transition from less-active to more active states.
- Published
- 2020
7. Characterization of Curtovirus V2 Protein, a Functional Homolog of Begomovirus V2
- Author
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Ministerio de Industria y Competitividad (España), 0000-0002-4806-253X, Luna, Ana P, Romero-Rodríguez, Beatriz, Rosas-Díaz, Tábata, Cerero, Laura, Rodríguez-Negrete, Edgar A, Castillo, Araceli G, Bejarano, Eduardo R, Ministerio de Industria y Competitividad (España), 0000-0002-4806-253X, Luna, Ana P, Romero-Rodríguez, Beatriz, Rosas-Díaz, Tábata, Cerero, Laura, Rodríguez-Negrete, Edgar A, Castillo, Araceli G, and Bejarano, Eduardo R
- Abstract
Geminiviruses are single-stranded DNA plant viruses with circular genomes packaged within geminate particles. Among the Geminiviridae family, Begomovirus and Curtovirus comprise the two best characterized genera. Curtovirus and Old World begomovirus possess similar genome structures with six to seven open-reading frames (ORF). Among them, begomovirus and curtovirus V2 ORFs share the same location in the viral genome, encode proteins of similar size, but show extremely poor sequence homology between the genera. V2 from Beet curly top virus (BCTV), the model species for the Curtovirus genus, as it begomoviral counterpart, suppresses post-transcriptional gene silencing (PTGS) by impairing the RDR6/SGS3 pathway and localizes in the nucleus spanning from the perinuclear region to the cell periphery. By aminoacid sequence comparison we have identified that curtoviral and begomoviral V2 proteins shared two hydrophobic domains and a putative phosphorylation motif. These three domains are essential for BCTV V2 silencing suppression activity, for the proper nuclear localization of the protein and for systemic infection. The lack of suppression activity in the mutated versions of V2 is complemented by the impaired function of RDR6 in Nicotiana benthamiana but the ability of the viral mutants to produce a systemic infection is not recovered in gene silencing mutant backgrounds. We have also demonstrated that, as its begomoviral homolog, V2 from BCTV is able to induce systemic symptoms and necrosis associated with a hypersensitive response-like (HR-like) when expressed from Potato virus X vector in N. benthamiana, and that this pathogenicity activity does not dependent of its ability to supress PTGS.
- Published
- 2020
8. Suppressor Analysis Uncovers That MAPs and Microtubule Dynamics Balance with the Cut7/ Kinesin-5 Motor for Mitotic Spindle Assembly in Schizosaccharomyces pombe
- Author
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Yukawa, Masashi, Yamada, Yusuke, Toda, Takashi, Yukawa, Masashi, Yamada, Yusuke, and Toda, Takashi
- Abstract
type:text, The Kinesin-5 motor Cut7 in Schizosaccharomyces pombe plays essential roles in spindle pole separation, leading to the assembly of bipolar spindle. In many organisms, simultaneous inactivation of Kinesin-14s neutralizes Kinesin-5 deficiency. To uncover the molecular network that counteracts Kinesin-5, we have conducted a genetic screening for suppressors that rescue the cut7-22 temperature sensitive mutation, and identified 10 loci. Next generation sequencing analysis reveals that causative mutations are mapped in genes encoding a-, b-tubulins and the microtubule plus-end tracking protein Mal3/EB1, in addition to the components of the Pkl1/Kinesin-14 complex. Moreover, the deletion of various genes required for microtubule nucleation/polymerization also suppresses the cut7 mutant. Intriguingly, Klp2/ Kinesin-14 levels on the spindles are significantly increased in cut7 mutants, whereas these increases are negated by suppressors, which may explain the suppression by these mutations/deletions. Consistent with this notion, mild overproduction of Klp2 in these double mutant cells confers temperature sensitivity. Surprisingly, treatment with a microtubule-destabilizing drug not only suppresses cut7 temperature sensitivity but also rescues the lethality resulting from the deletion of cut7, though a single klp2 deletion per se cannot compensate for the loss of Cut7. We propose that microtubule assembly and/or dynamics antagonize Cut7 functions, and that the orchestration between these two factors is crucial for bipolar spindle assembly., This work was supported by the Japan Society for the Promotion of Science (JSPS) [KAKENHI Scientific Research (A) (16H02503 to T.T.), a Challenging Exploratory Research grant (16K14672 to T.T.), Scientific Research (C) (16K07694 to M.Y.)], the Naito Foundation (T.T.) and the Uehara Memorial Foundation (T.T). M.Y. and T.T. designed research.M.Y. and Y.Y. performed experiments and analyzed the data.
- Published
- 2019
9. Essential Saccharomyces cerevisiae genome instability suppressing genes identify potential human tumor suppressors.
- Author
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Srivatsan, Anjana, Srivatsan, Anjana, Li, Binzhong, Sanchez, Dafne N, Somach, Steven B, da Silva, Vandeclecio L, de Souza, Sandro J, Putnam, Christopher D, Kolodner, Richard D, Srivatsan, Anjana, Srivatsan, Anjana, Li, Binzhong, Sanchez, Dafne N, Somach, Steven B, da Silva, Vandeclecio L, de Souza, Sandro J, Putnam, Christopher D, and Kolodner, Richard D
- Abstract
Gross Chromosomal Rearrangements (GCRs) play an important role in human diseases, including cancer. Although most of the nonessential Genome Instability Suppressing (GIS) genes in Saccharomyces cerevisiae are known, the essential genes in which mutations can cause increased GCR rates are not well understood. Here 2 S. cerevisiae GCR assays were used to screen a targeted collection of temperature-sensitive mutants to identify mutations that caused increased GCR rates. This identified 94 essential GIS (eGIS) genes in which mutations cause increased GCR rates and 38 candidate eGIS genes that encode eGIS1 protein-interacting or family member proteins. Analysis of TCGA data using the human genes predicted to encode the proteins and protein complexes implicated by the S. cerevisiae eGIS genes revealed a significant enrichment of mutations affecting predicted human eGIS genes in 10 of the 16 cancers analyzed.
- Published
- 2019
10. The Plastid Lipocalin LCNP Is Required for Sustained Photoprotective Energy Dissipation in Arabidopsis.
- Author
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Malnoë, Alizée, Malnoë, Alizée, Schultink, Alex, Shahrasbi, Sanya, Rumeau, Dominique, Havaux, Michel, Niyogi, Krishna K, Malnoë, Alizée, Malnoë, Alizée, Schultink, Alex, Shahrasbi, Sanya, Rumeau, Dominique, Havaux, Michel, and Niyogi, Krishna K
- Abstract
Light utilization is finely tuned in photosynthetic organisms to prevent cellular damage. The dissipation of excess absorbed light energy, a process termed nonphotochemical quenching (NPQ), plays an important role in photoprotection. Little is known about the sustained or slowly reversible form(s) of NPQ and whether they are photoprotective, in part due to the lack of mutants. The Arabidopsis thaliana suppressor of quenching1 (soq1) mutant exhibits enhanced sustained NPQ, which we term qH. To identify molecular players involved in qH, we screened for suppressors of soq1 and isolated mutants affecting either chlorophyllide a oxygenase or the chloroplastic lipocalin, now renamed plastid lipocalin (LCNP). Analysis of the mutants confirmed that qH is localized to the peripheral antenna (LHCII) of photosystem II and demonstrated that LCNP is required for qH, either directly (by forming NPQ sites) or indirectly (by modifying the LHCII membrane environment). qH operates under stress conditions such as cold and high light and is photoprotective, as it reduces lipid peroxidation levels. We propose that, under stress conditions, LCNP protects the thylakoid membrane by enabling sustained NPQ in LHCII, thereby preventing singlet oxygen stress.
- Published
- 2018
11. MicroRNA-191-5p exerts a tumor suppressive role in renal cell carcinoma
- Author
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Chen, Peijie, Pan, Xiang, Zhao, Liwen, Jin, Lu, Lin, Canbin, Quan, Jing, He, Tao, Zhou, Liang, Wu, Xueling, Wang, Yong, Ni, Liangchao, Yang, Shangqi, Lai, Yongqing, Chen, Peijie, Pan, Xiang, Zhao, Liwen, Jin, Lu, Lin, Canbin, Quan, Jing, He, Tao, Zhou, Liang, Wu, Xueling, Wang, Yong, Ni, Liangchao, Yang, Shangqi, and Lai, Yongqing
- Abstract
Renal cell carcinoma (RCC) is a common tumor of the urinary system. Previously, miR-191-5p has been reported to be associated with various types of cancer; however, its specific functions in RCC have not been investigated to date. In the present study, the expression of miR-191-5p in the 786-O and ACHN cell lines was detected in vitro by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The results of RT-qPCR revealed that miR-191-5p was significantly downregulated in the two cell lines compared with the 293T cell line. miR-191-5p was also significantly downregulated in RCC tissue compared with paired normal tissue. In addition, the effects of miR-191-5p on cell proliferation, migration, invasion and apoptosis were examined by CCK-8, MTT, wound scratch, Transwell and flow cytometry assays. Downregulation of miR-191-5p was observed to promote cell proliferation, migration and invasion, as well as to repress the cell apoptosis of 786-O and ACHN cells. Therefore, the current study suggests that miR-191-5p functions as a tumor suppressor in RCC. Further studies are required to uncover the underlying signaling pathway of miR-191-5p and its potential role as a biomarker for early detection and prognosis prediction, and as a therapeutic target of RCC.
- Published
- 2018
12. Common and divergent features of galactose-1-phosphate and fructose-1-phosphate toxicity in yeast.
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Gibney, Patrick A, Drubin, David G1, Gibney, Patrick A, Schieler, Ariel, Chen, Jonathan C, Bacha-Hummel, Jessie M, Botstein, Maxim, Volpe, Matthew, Silverman, Sanford J, Xu, Yifan, Bennett, Bryson D, Rabinowitz, Joshua D, Botstein, David, Gibney, Patrick A, Drubin, David G1, Gibney, Patrick A, Schieler, Ariel, Chen, Jonathan C, Bacha-Hummel, Jessie M, Botstein, Maxim, Volpe, Matthew, Silverman, Sanford J, Xu, Yifan, Bennett, Bryson D, Rabinowitz, Joshua D, and Botstein, David
- Abstract
Metabolic dysregulation leading to sugar-phosphate accumulation is toxic in organisms ranging from bacteria to humans. By comparing two models of sugar-phosphate toxicity in Saccharomyces cerevisiae, we demonstrate that toxicity occurs, at least in part, through multiple, isomer-specific mechanisms, rather than a single general mechanism.
- Published
- 2018
13. The Promiscuous sumA Missense Suppressor from Salmonella enterica Has an Intriguing Mechanism of Action.
- Author
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Cole, Ashley E, Cole, Ashley E, Hani, Fatmah M, Altman, Ronni, Meservy, Megan, Roth, John R, Altman, Elliot, Cole, Ashley E, Cole, Ashley E, Hani, Fatmah M, Altman, Ronni, Meservy, Megan, Roth, John R, and Altman, Elliot
- Abstract
While most missense suppressors have very narrow specificities and only suppress the allele against which they were isolated, the sumA missense suppressor from Salmonella enterica serovar Typhimurium is a promiscuous or broad-acting missense suppressor that suppresses numerous missense mutants. The sumA missense suppressor was identified as a glyV tRNA Gly3(GAU/C) missense suppressor that can recognize GAU or GAC aspartic acid codons and insert a glycine amino acid instead of aspartic acid. In addition to rescuing missense mutants caused by glycine to aspartic acid changes as expected, sumA could also rescue a number of other missense mutants as well by changing a neighboring (contacting) aspartic acid to glycine, which compensated for the other amino acid change. Thus the ability of sumA to rescue numerous missense mutants was due in part to the large number of glycine codons in genes that can be mutated to an aspartic acid codon and in part to the general tolerability and/or preference for glycine amino acids in proteins. Because the glyV tRNA Gly3(GAU/C) missense suppressor has also been extensively characterized in Escherichia coli as the mutA mutator, we demonstrated that all gain-of-function mutants isolated in a glyV tRNA Gly3(GAU/C) missense suppressor are transferable to a wild-type background and thus the increased mutation rates, which occur in glyV tRNA Gly3(GAU/C) missense suppressors, are not due to the suppression of these mutants.
- Published
- 2017
14. IGDB-2, an Ig/FNIII protein, binds the ion channel LGC-34 and controls sensory compartment morphogenesis in C. elegans.
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Wang, Wendy, Wang, Wendy, Perens, Elliot A, Oikonomou, Grigorios, Wallace, Sean W, Lu, Yun, Shaham, Shai, Wang, Wendy, Wang, Wendy, Perens, Elliot A, Oikonomou, Grigorios, Wallace, Sean W, Lu, Yun, and Shaham, Shai
- Abstract
Sensory organ glia surround neuronal receptive endings (NREs), forming a specialized compartment important for neuronal activity, and reminiscent of glia-ensheathed synapses in the central nervous system. We previously showed that DAF-6, a Patched-related protein, is required in glia of the C. elegans amphid sensory organ to restrict sensory compartment size. LIT-1, a Nemo-like kinase, and SNX-1, a retromer component, antagonize DAF-6 and promote compartment expansion. To further explore the machinery underlying compartment size control, we sought genes whose inactivation restores normal compartment size to daf-6 mutants. We found that mutations in igdb-2, encoding a single-pass transmembrane protein containing Ig-like and fibronectin type III domains, suppress daf-6 mutant defects. IGDB-2 acts in glia, where it localizes to glial membranes surrounding NREs, and, together with LIT-1 and SNX-1, regulates compartment morphogenesis. Immunoprecipitation followed by mass spectrometry demonstrates that IGDB-2 binds to LGC-34, a predicted ligand-gated ion channel, and lgc-34 mutations inhibit igdb-2 suppression of daf-6. Our findings reveal a novel membrane protein complex and suggest possible mechanisms for how sensory compartment size is controlled.
- Published
- 2017
15. A viral suppressor of RNA silencing inhibits ARGONAUTE 1 function by precluding target RNA binding to pre-assembled RISC
- Author
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#NODATA#, 0000-0001-5628-6632, Kenesi, Erzsébet, Carbonell, Alberto, Lózsa, Rita, Vértessy, Beáta, Lakatos, Lóránt, #NODATA#, 0000-0001-5628-6632, Kenesi, Erzsébet, Carbonell, Alberto, Lózsa, Rita, Vértessy, Beáta, and Lakatos, Lóránt
- Abstract
In most eukaryotes, RNA silencing is an adaptive immune system regulating key biological processes including antiviral defense. To evade this response, viruses of plants, worms and insects have evolved viral suppressors of RNA silencing proteins (VSRs). Various VSRs, such as P1 from Sweet potato mild mottle virus (SPMMV), inhibit the activity of RNA-induced silencing complexes (RISCs) including an ARGONAUTE (AGO) protein loaded with a small RNA. However, the specific mechanisms explaining this class of inhibition are unknown. Here, we show that SPMMV P1 interacts with AGO1 and AGO2 from Arabidopsis thaliana, but solely interferes with AGO1 function. Moreover, a mutational analysis of a newly identified zinc finger domain in P1 revealed that this domain could represent an effector domain as it is required for P1 suppressor activity but not for AGO1 binding. Finally, a comparative analysis of the target RNA binding capacity of AGO1 in the presence of wild-type or suppressor-defective P1 forms revealed that P1 blocks target RNA binding to AGO1. Our results describe the negative regulation of RISC, the small RNA containing molecular machine.
- Published
- 2017
16. Fastest Time to Cancer by Loss of Tumor Suppressor Genes or Oncogene Activation
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SANCHEZ TAPIA, CYNTHIA HIXAHUARY, Wan, Frederic Y. M.1, SANCHEZ TAPIA, CYNTHIA HIXAHUARY, SANCHEZ TAPIA, CYNTHIA HIXAHUARY, Wan, Frederic Y. M.1, and SANCHEZ TAPIA, CYNTHIA HIXAHUARY
- Abstract
Genetic instability promotes cancer progression (by increasing the probability of cancerous mutations) as well as hinders it (by imposing a higher cell death rate for cells susceptible to cancerous mutation).With oncogene activation or the loss of tumor suppressor gene functions known to be responsible for a high percentage of breast and colorectal cancer (and a good fraction of lung cancer and other types as well), it is important to understand how genetic instability can be orchestrated toward carcinogenesis. In this context, this research gives a complete characterization of the optimal cell mutation rate for the fastest time to a target cancerous cell population through the loss of both copies of a tumor suppressor gene or through oncogene activation.
- Published
- 2016
17. Identification of Suppressors of a Cold-Sensitive Receptor-Like Kinase Mutant in Arabidopsis thaliana
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Wellington, Rachel Courtney and Wellington, Rachel Courtney
- Abstract
Long-distance signaling is an important process in the development of Arabidopsis thaliana. A leucine-rich repeat receptor-like kinase (LRR-RLK), XYLEM INTERMIXED WITH PHLOEM1 a.k.a. C-TERMINALLY ENCODED PEPTIDE RECEPTOR 1 (XIP1/CEPR1), functions in vascular development and has recently been implicated in nitrogen sensing and response. Previous results indicate that XIP1/CEPR1 also interacts with multiple proteins involved in sugar metabolism and transport as well as other metabolic proteins, which indicates a possible role for XIP1/CEPR1 in mediating sugar transport. xip1-1 seeds, which grow slowly in the cold in comparison to Columbia wild-type plants, were previously EMS mutagenized and screened for suppressors of the cold-sensitive phenotype. One of these suppressors, 9-12, maps to the lower region of chromosome V and several possible causative EMS-like mutations have been identified that may link XIP1/CEPR1 to a more general vascular transport role.
- Published
- 2016
18. Genetic Suppressors of mrp-5 Lethality in C. elegans
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Beardsley, Simon and Beardsley, Simon
- Abstract
Heme is an essential cofactor in numerous proteins, but is also cytotoxic. Thus, directed pathways must exist for regulating heme homeostasis. C. elegans is a powerful genetic animal model for elucidating these pathways because it is a heme auxotroph. Worms acquire dietary heme though HRG-1-related importers, and intestinal export was demonstrated to be mediated by the ABC transporter MRP-5. Loss of mrp-5 results in embryonic lethality. Although heme transporters have been identified, there are significant gaps in our understanding for the heme trafficking beyond HRG-1 and MRP-5. To identify additional components, we conducted a forward genetic screen utilizing the null allele mrp-5(ok2067). Screening of 160,000 haploid genomes yielded thirty-two mrp-5(ok2067) suppressor mutants. Deep-sequencing variant analysis revealed three of the suppressors subunits of adapter protein complex 3 (AP-3). We now seek to identify mechanisms for how adaptor protein deficiencies bypass a defect in MRP-5-mediated heme export.
- Published
- 2016
19. DOWNY MILDEW RESISTANT 6 and DMR6-LIKE OXYGENASE 1 are partially redundant but distinct suppressors of immunity in Arabidopsis
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Zeilmaker, Tieme, Ludwig, N.R., Elberse, Joyce, Seidl, M.F., Berke, Lidija, Van Doorn, Arjen, Schuurink, Robert C., Snel, Berend, Van Den Ackerveken, Guido, Zeilmaker, Tieme, Ludwig, N.R., Elberse, Joyce, Seidl, M.F., Berke, Lidija, Van Doorn, Arjen, Schuurink, Robert C., Snel, Berend, and Van Den Ackerveken, Guido
- Abstract
Arabidopsis downy mildew resistant 6 (dmr6) mutants have lost their susceptibility to the downy mildew Hyaloperonospora arabidopsidis. Here we show that dmr6 is also resistant to the bacterium Pseudomonas syringae and the oomycete Phytophthora capsici. Resistance is accompanied by enhanced defense gene expression and elevated salicylic acid levels. The suppressive effect of the DMR6 oxygenase was confirmed in transgenic Arabidopsis lines overexpressing DMR6 that show enhanced susceptibility to H. arabidopsidis, P. capsici, and P. syringae. Phylogenetic analysis of the superfamily of 2-oxoglutarate Fe(II)-dependent oxygenases revealed a subgroup of DMR6-LIKE OXYGENASEs (DLOs). Within Arabidopsis, DMR6 is most closely related to DLO1 and DLO2. Overexpression of DLO1 and DLO2 in the dmr6 mutant restored the susceptibility to downy mildew indicating that DLOs negatively affect defense, similar to DMR6. DLO1, but not DLO2, is co-expressed with DMR6, showing strong activation during pathogen attack and following salicylic acid treatment. DMR6 and DLO1 differ in their spatial expression pattern in downy mildew-infected Arabidopsis leaves; DMR6 is mostly expressed in cells that are in contact with hyphae and haustoria of H. arabidopsidis, while DLO1 is expressed mainly in the vascular tissues near infection sites. Strikingly, the dmr6-3-dlo1 double mutant, that is completely resistant to H. arabidopsidis, showed a strong growth reduction that was associated with high levels of salicylic acid. We conclude that DMR6 and DLO1 redundantly suppress plant immunity, but also have distinct activities based on their differential localization of expression.
- Published
- 2015
20. Positive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African Buffalo: a plausible new mechanism for a high frequency anomaly.
- Author
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van Hooft, Pim, van Hooft, Pim, Greyling, Ben J, Getz, Wayne M, van Helden, Paul D, Zwaan, Bas J, Bastos, Armanda DS, van Hooft, Pim, van Hooft, Pim, Greyling, Ben J, Getz, Wayne M, van Helden, Paul D, Zwaan, Bas J, and Bastos, Armanda DS
- Abstract
Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important implicatio
- Published
- 2014
21. Mosquito-Borne Viruses and Suppressors of Invertebrate Antiviral RNA Silencing
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O'Neal, Scott T., Samuel, Glady Hazitha, Adelman, Zach N., Myles, Kevin M., O'Neal, Scott T., Samuel, Glady Hazitha, Adelman, Zach N., and Myles, Kevin M.
- Abstract
The natural maintenance cycles of many mosquito-borne viruses require establishment of persistent non-lethal infections in the invertebrate host. While the mechanisms by which this occurs are not well understood, antiviral responses directed by small RNAs are important in modulating the pathogenesis of viral infections in disease vector mosquitoes. In yet another example of an evolutionary arms race between host and pathogen, some plant and insect viruses have evolved to encode suppressors of RNA silencing (VSRs). Whether or not mosquito-borne viral pathogens encode VSRs has been the subject of debate. While at first there would seem to be little evolutionary benefit to mosquito-borne viruses encoding proteins or sequences that strongly interfere with RNA silencing, we present here a model explaining how the expression of VSRs by these viruses in the vector might be compatible with the establishment of persistence. We also discuss the challenges associated with interrogating these viruses for the presence of suppressor proteins or sequences, as well as the candidates that have been identified in the genomes of mosquito-borne pathogens thus far.
- Published
- 2014
- Full Text
- View/download PDF
22. miRNA modulation of SOCS1 using an influenza A virus delivery system
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Izzard,L, Ye,S, Jenkins,K, Xia,Y, Tizard,M, Stambas,J, Izzard,L, Ye,S, Jenkins,K, Xia,Y, Tizard,M, and Stambas,J
- Abstract
Difficulties associated with efficient delivery and targeting of miRNAs to cells is hampering the real world application of miRNA technology. This study utilized an influenza A-based delivery system to express miR-155 in order to knockdown SOCS1 mRNA. Using qPCR and dual luciferase technology we show that miR-155 delivery resulted in a significant increase in cellular miR-155 which facilitated a downregulation of SOCS1 gene expression and a functional increase in IL-6 and IFN-β cytokines.
- Published
- 2014
23. Genetic screens for floral mutants in Arabidopsis thaliana: enhancers and suppressors.
- Author
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Dinh, Thanh Theresa, Dinh, Thanh Theresa, Luscher, Elizabeth, Li, Shaofang, Liu, Xigang, Won, So Youn, Chen, Xuemei, Dinh, Thanh Theresa, Dinh, Thanh Theresa, Luscher, Elizabeth, Li, Shaofang, Liu, Xigang, Won, So Youn, and Chen, Xuemei
- Abstract
The flower is a hallmark feature that has contributed to the evolutionary success of land plants. Diverse mutagenic agents have been employed as a tool to genetically perturb flower development and identify genes involved in floral patterning and morphogenesis. Since the initial studies to identify genes governing processes such as floral organ specification, mutagenesis in sensitized backgrounds has been used to isolate enhancers and suppressors to further probe the molecular basis of floral development. Here, we first describe two commonly employed methods for mutagenesis (using ethyl methanesulfonate (EMS) or T-DNAs as mutagens), and then describe three methods for identifying a mutation that leads to phenotypic alterations--traditional map-based cloning, TAIL-PCR, and deep sequencing in the plant model Arabidopsis thaliana.
- Published
- 2014
24. Systematic analyses of rpm-1 suppressors reveal roles for ESS-2 in mRNA splicing in Caenorhabditis elegans.
- Author
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Noma, Kentaro, Noma, Kentaro, Goncharov, Alexandr, Jin, Yishi, Noma, Kentaro, Noma, Kentaro, Goncharov, Alexandr, and Jin, Yishi
- Abstract
The PHR (Pam/Highwire/RPM-1) family of ubiquitin E3 ligases plays conserved roles in axon patterning and synaptic development. Genetic modifier analysis has greatly aided the discovery of the signal transduction cascades regulated by these proteins. In Caenorhabditis elegans, loss of function in rpm-1 causes axon overgrowth and aberrant presynaptic morphology, yet the mutant animals exhibit little behavioral deficits. Strikingly, rpm-1 mutations strongly synergize with loss of function in the presynaptic active zone assembly factors, syd-1 and syd-2, resulting in severe locomotor deficits. Here, we provide ultrastructural evidence that double mutants, between rpm-1 and syd-1 or syd-2, dramatically impair synapse formation. Taking advantage of the synthetic locomotor defects to select for genetic suppressors, previous studies have identified the DLK-1 MAP kinase cascade negatively regulated by RPM-1. We now report a comprehensive analysis of a large number of suppressor mutations of this screen. Our results highlight the functional specificity of the DLK-1 cascade in synaptogenesis. We also identified two previously uncharacterized genes. One encodes a novel protein, SUPR-1, that acts cell autonomously to antagonize RPM-1. The other affects a conserved protein ESS-2, the homolog of human ES2 or DGCR14. Loss of function in ess-2 suppresses rpm-1 only in the presence of a dlk-1 splice acceptor mutation. We show that ESS-2 acts to promote accurate mRNA splicing when the splice site is compromised. The human DGCR14/ES2 resides in a deleted chromosomal region implicated in DiGeorge syndrome, and its mutation has shown high probability as a risk factor for schizophrenia. Our findings provide the first functional evidence that this family of proteins regulate mRNA splicing in a context-specific manner.
- Published
- 2014
25. Mosquito-Borne Viruses and Suppressors of Invertebrate Antiviral RNA Silencing
- Author
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Entomology, Fralin Life Sciences Institute, O'Neal, Scott T., Samuel, Glady Hazitha, Adelman, Zach N., Myles, Kevin M., Entomology, Fralin Life Sciences Institute, O'Neal, Scott T., Samuel, Glady Hazitha, Adelman, Zach N., and Myles, Kevin M.
- Abstract
The natural maintenance cycles of many mosquito-borne viruses require establishment of persistent non-lethal infections in the invertebrate host. While the mechanisms by which this occurs are not well understood, antiviral responses directed by small RNAs are important in modulating the pathogenesis of viral infections in disease vector mosquitoes. In yet another example of an evolutionary arms race between host and pathogen, some plant and insect viruses have evolved to encode suppressors of RNA silencing (VSRs). Whether or not mosquito-borne viral pathogens encode VSRs has been the subject of debate. While at first there would seem to be little evolutionary benefit to mosquito-borne viruses encoding proteins or sequences that strongly interfere with RNA silencing, we present here a model explaining how the expression of VSRs by these viruses in the vector might be compatible with the establishment of persistence. We also discuss the challenges associated with interrogating these viruses for the presence of suppressor proteins or sequences, as well as the candidates that have been identified in the genomes of mosquito-borne pathogens thus far.
- Published
- 2014
26. WT1 promotes cell proliferation in non-small cell lung cancer cell lines through up-regulating cyclin D1 and p-pRb in vitro and in vivo
- Author
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Xu, Caihua, Wu, Chen, Xia, Yang, Zhong, Zhaopeng, Liu, Xiang, Xu, Jing, Cui, Fei, Chen, Bin, Røe, Oluf Dimitri, Li, Aihong, Chen, Yijiang, Xu, Caihua, Wu, Chen, Xia, Yang, Zhong, Zhaopeng, Liu, Xiang, Xu, Jing, Cui, Fei, Chen, Bin, Røe, Oluf Dimitri, Li, Aihong, and Chen, Yijiang
- Abstract
The Wilms' tumor suppressor gene (WT1) has been identified as an oncogene in many malignant diseases such as leukaemia, breast cancer, mesothelioma and lung cancer. However, the role of WT1 in non-small-cell lung cancer (NSCLC) carcinogenesis remains unclear. In this study, we compared WT1 mRNA levels in NSCLC tissues with paired corresponding adjacent tissues and identified significantly higher expression in NSCLC specimens. Cell proliferation of three NSCLC cell lines positively correlated with WT1 expression; moreover, these associations were identified in both cell lines and a xenograft mouse model. Furthermore, we demonstrated that up-regulation of Cyclin D1 and the phosphorylated retinoblastoma protein (p-pRb) was mechanistically related to WT1 accelerating cells to S-phase. In conclusion, our findings demonstrated that WT1 is an oncogene and promotes NSCLC cell proliferation by up-regulating Cyclin D1 and p-pRb expression.
- Published
- 2013
- Full Text
- View/download PDF
27. The lineage-defining factors T-bet and Bcl-6 collaborate to regulate Th1 gene expression patterns
- Author
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Oestreich, Kenneth J., Huang, A. C., Weinmann, A. S., Oestreich, Kenneth J., Huang, A. C., and Weinmann, A. S.
- Published
- 2011
- Full Text
- View/download PDF
28. Some mechanisms responsible for the vividness of mental imagery : suppressor, closer, and other functions
- Author
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Hishitani, Shinsuke, Miyazaki, Takuya, Motoyama, Hiroki, Hishitani, Shinsuke, Miyazaki, Takuya, and Motoyama, Hiroki
- Abstract
In this paper, studies concerned with the vividness of imagery are reviewed to elucidate the characteristics of vivid imagery, the mechanisms responsible for the vividness of imagery, and the factors that affect those mechanisms. From this review, the following characteristics of imagery can be identified: (a) imagery vividness can be defined by the amount of information in the image, and more perceptual information is in vivid than in dim imagery; (b) information structure in long-term memory (LTM) consists of meaning, affective information, perceptual information, and motoric information, and those components are interconnected; (c) imagery is generated in the image construction stages using perceptual information; (d) a mechanism called the Suppressor controls the channel capacity, or the flow of perceptual information from LTM to the image construction stages; (e) the degree of this suppression is affected by the emotional value of imagery computed on the basis of affective information stored in LTM; (f) motoric information in LTM also influences vividness by acting on the image construction stages. Given these characteristics, we propose a model of imagery processes in order to explain how a certain level of vividness is established for the visual mental image. Finally, some neural correlates of the model are described based on results from our latest fMRI studies, and problems remaining for further development of the model are discussed.
- Published
- 2011
29. Changes in complement responses in Gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) under crowding stress, plus viral and bacterial challenges
- Author
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Mauri, I., Romero Jódar, Alejandro, Acerete, L., Mackenzie, Simon, Roher, N., Calloi, A., Cano, I., Álvarez, M. Carmen, Tort, Lluis, Mauri, I., Romero Jódar, Alejandro, Acerete, L., Mackenzie, Simon, Roher, N., Calloi, A., Cano, I., Álvarez, M. Carmen, and Tort, Lluis
- Abstract
Gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) were subjected to either experimental infection with Photobacterium damselae subsp. piscicida or Nodavirus after a period of 2 weeks of crowding in which fish were subjected to a 5-fold increase in density (10e50 kg/m3). Samples were obtained before the crowding period (0 h or control) and at 24 h and 72 h after crowding from both groups of infected fish. The Complement haemolytic activity and the expression of the C3 gene were evaluated in blood and liver samples respectively. The bacteriolytic and lysozyme activities were also assessed. The results showed that Complement haemolytic activity was reduced at 72 h with both bacteria and virus in high density Gilthead seabream, and a similar increase was observed at low density. Bacteriolytic activity under both bacterial and viral challenges for both species was increased at 24 h, under low density. At high density, the bacterial challenge did not induce significant changes. C3 mRNA abundance was substantially increased after pathogen treatments in low density groups at 24 h but no significant changes were detected at high densities. These results support the idea of the suppressor effect of stressors on the immune system since a reduction of Complement activity under virus and high density, or lack of response in C3 expression under high density were observed.
- Published
- 2011
30. The emotional manipulation-psychopathy nexus: Relationships with emotional intelligence, alexithymia and ethical position
- Author
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Grieve, Rachel, Mahar, Doug, Grieve, Rachel, and Mahar, Doug
- Abstract
This research examined for the first time the relationship between emotional manipulation, emotional intelligence, and primary and secondary psychopathy. As predicted, in Study 1 (N = 73), emotional manipulation was related to both primary and secondary psychopathy. Only secondary psychopathy was related to perceived poor emotional skills. Secondary psychopathy was also related to emotional concealment. Emotional intelligence was negatively related to perceived poor emotional skills, emotional concealment, and primary and secondary psychopathy. In Study 2 (N = 275), two additional variables were included: alexithymia and ethical position. It was found that for males, primary psychopathy and emotional intelligence predicted emotional manipulation, while for females emotional intelligence acted as a suppressor, and ethical idealism and secondary psychopathy were additional predictors. For males, emotional intelligence and alexithymia were related to perceived poor emotional skills, while for females emotional intelligence, but not alexithymia, predicted perceived poor emotional skills, with ethical idealism acting as a suppressor. For both males and females, alexithymia predicted emotional concealment. These findings suggest that the mechanisms behind the emotional manipulation–psychopathy relationship differ as a function of gender. Examining the different aspects of emotional manipulation as separate but related constructs may enhance understanding of the construct of emotional manipulation.
- Published
- 2010
31. HANDSFREE-ENHET FÖR MOBIL TRYGGHETSTELEFON
- Author
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Sundberg, Daniel and Sundberg, Daniel
- Abstract
Cnior Mobile AB i Lindesberg utvecklar en mobil trygghetstelefon för äldre. Detta examensarbete går ut på att utforma en handsfree-enhet för denna. Handsfree-enheten ska integreras i larmknappen, som bärs av användaren runt handleden, och har kontakt med telefonen via blåtandsradio. I examensarbetet ingår att välja ut lämplig högtalare och mikrofon, hitta lösningar för smuts- och vattentålighet samt att lösa problem med ekon och bakgrundsstörningar. En högtalare hittades som uppfyllde kraven för smuts- och vattentålighet samtidigt som den hade utmärkt frekvensgång för återgivning av tydligt tal. Vattenavrinning från högtalaren löstes genom att ett sinussvep sänds ut från högtalaren varje gång ett samtal ska kopplas upp. På så sätt pressar ljudtrycket ut vattnet från handledsknappens kavitet. Olika utformningar av ljudhålen i handledsknappens skal provades. Den bästa lösningen för vattenavrinningen var att använda sju stycken runda hål med 1,3 mm i diameter. En ljudtrycksmätning säkerställde att ljudtrycket inte blev lidande av denna utformning av ljudhålen. Ekosläckning och bakgrundsstörningsundertryckning sköts av GSM-modulen i trygghetsmobilen. I ekosläckningens manual finns beskrivet hur ekosläckningens 24 parametrar kan justeras för att passa olika applikationer. Endast en mindre ändring av de rekommenderade parametervärdena behövdes för att ekosläckning och bakgrundsstörningsundertryckning skulle fungera tillfredställande. Eftersom mikrofonernas datablad visade på så snarlika egenskaper överlämnades mikrofonvalet till företaget, då det kan vara klokt att låta priset avgöra.
- Published
- 2009
32. Mutations in the BRCA1 gene (185delAG and 5382insC) are not present in any of the 30 breast cancer patients analyzed from eastern Colombia
- Author
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Sanabria, María Carolina, Muñoz, Gerardo, Vargas, Clara Inés, Sanabria, María Carolina, Muñoz, Gerardo, and Vargas, Clara Inés
- Abstract
Introduction. Breast cancer is considered a worldwide public health problem, and, in Santander Province, Colombia, it is the first leading cause of morbidity and mortality by cancer in women. All cancers are considered genetic diseases, and mutations in BRCA (BReast CAncer) genes raises the risk for breast cancer by 60%-80%. The current study searched for the two most frequent BRCA1 mutations reported in the Breast Cancer Core Information database.Objective. The presence of specific mutations (185delAG, exon 2 and 5382insC, exon 20) was determined for the BRCA1 gene in women with familial/hereditary breast cancer.Materials and methods. The sample included 30 female patients using the oncology services in Bucaramanga, eastern Colombia; an informed consent, a questionnaire and a blood sample were obtained from each. The molecular analysis was done with PCR-Mismatch, to detect the insertion or eliminatation of a restriction site, and enzymatic digestion methods (HinfI or DdeI).Results. Two of the most frequent BRCA1 mutations in the international database were not found in the 30 patients studied.Conclusion. Additional mutation screening techniques are necessary involving the entire BRCA1 gene, are necessary in order to better characterize the molecular epidemiology of breast cancer in Bucaramanga, Santander, Colombia., Introducción. El cáncer de mama es un problema de salud pública a nivel mundial y en Santander es la primera causa de morbimortalidad por cáncer en mujeres. Todo cáncer se considera una enfermedad genética y las mutaciones en los genes BRCA confieren un riesgo de 60% a 80% para el cáncer de mama. Este estudio consistió en buscar las dos mutaciones BRCA1 más frecuentes según la base de datos Breast Cancer Core Information.Objetivo. Determinar la presencia de mutaciones específicas (185delAG, exón 2, y 5382insC, exón 20) en el gen BRCA1 en mujeres con cáncer de mama heredo-familiar, atendidas en los diferentes servicios de oncología de Bucaramanga, Colombia.Materiales y métodos. La muestra incluyó 30 pacientes, de las cuales se obtuvo un consentimiento informado, un cuestionario dirigido y sangre venosa para los estudios moleculares. El análisis molecular se realizó mediante PCR-mismatch, para introducir o eliminar sitios de restricción, y digestión enzimática (HinfI o DdeI).Resultados. No se detectaron dos de las mutaciones más frecuentes en el gen BRCA1 en las 30 pacientes estudiadas.Conclusión. Se requieren más estudios en la región que abarquen la tamización de la totalidad del gen BRCA1, para hacer una mayor contribución al conocimiento de la epidemiología molecular del cáncer de mama en Bucaramanga, Santander, Colombia.
- Published
- 2009
33. Environmental signal integration by a modular AND gate.
- Author
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Anderson, J Christopher, Anderson, J Christopher, Voigt, Christopher A, Arkin, Adam P, Anderson, J Christopher, Anderson, J Christopher, Voigt, Christopher A, and Arkin, Adam P
- Abstract
Microorganisms use genetic circuits to integrate environmental information. We have constructed a synthetic AND gate in the bacterium Escherichia coli that integrates information from two promoters as inputs and activates a promoter output only when both input promoters are transcriptionally active. The integration occurs via an interaction between an mRNA and tRNA. The first promoter controls the transcription of a T7 RNA polymerase gene with two internal amber stop codons blocking translation. The second promoter controls the amber suppressor tRNA supD. When both components are transcribed, T7 RNA polymerase is synthesized and this in turn activates a T7 promoter. Because inputs and outputs are promoters, the design is modular; that is, it can be reconnected to integrate different input signals and the output can be used to drive different cellular responses. We demonstrate this modularity by wiring the gate to integrate natural promoters (responding to Mg(2+) and AI-1) and using it to implement a phenotypic output (invasion of mammalian cells). A mathematical model of the transfer function is derived and parameterized using experimental data.
- Published
- 2007
34. Von Hippel-Lindau tomour suppressor gene is not involved in sporadic human breast cancer
- Author
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Sourvinos, George, Miyakis, Spyridon, Liloglou, Triantafyllos L, Field, J, Spandidos, Demetrios A, Sourvinos, George, Miyakis, Spyridon, Liloglou, Triantafyllos L, Field, J, and Spandidos, Demetrios A
- Abstract
Objective: Mutations of the von Hippel-Lindau (vhf) gene, as well as allelic loss at the gene region (3p25-26) have been described in sporadic cases of the tumour types participating in VHL disease, but also in cancers not associated with the syndrome. In this study, we attempted mutation analysis of the vhf gene, as well as detection of allelic loss at 3p25-26 in sporadic human breast cancer. Methods: Eighty-two tumour specimens were screened for loss of heterozygosity (LOH) at the vhf region, and compared to the adjacent, histologically normal tissue. Furthermore, mutations within the three exons of vhf in the same panel of tumours were detected using SSCP and heteroduplex analysis and direct sequencing. Results: To our knowledge this is the first mutational analysis reported for the vhf gene in breast cancer, however we failed to reveal any mutations in the specimens examined. All the cases were informative for at least one of the microsatellite markers tested, 24 (29.2%) exhibited LOH at 3p25-26. Clinical and pathological data were available for all tumours examined, however no significant correlations were encountered. Conclusion: These results strongly indicate against a critical involvement of the tumour suppressor vhf in breast carcinogenesis.
- Published
- 2001
35. Separation and purification of plasmid mixtures by continuous elution electrophoresis.
- Author
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Prieto, DA, Prieto, DA, Harvey, LK, Nelson, EL, Prieto, DA, Prieto, DA, Harvey, LK, and Nelson, EL
- Published
- 2000
36. The Von Hippel-Lindau (VHL) tumor-suppressor gene is not mutated in sporadic human colon adenocarcinomas
- Author
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Miyakis, Spyridon and Miyakis, Spyridon
- Abstract
Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome, where the affected kindreds manifest multiple tumors, mainly of the central nervous system, renal and pancreatic tissue (Maher and Kaelin, 1997). The gene responsible for the disorder is a tumor-suppressor gene (Latif et al., 1993). Numerous germline mutations of VHL gene have been identified among families with various patterns of disease phenotypes (Zbar et al., 1996). Mutations of VHL, as well as allelic loss at the gene locus 3p25-26, have been repeatedly described in series from sporadic cases of the tumor types involved in VHL disease (Bailly et al., 1995; Lee et al., 1998). Frequent detection of somatic mutations of the gene in renal clear cell carcinoma (Gnarra et al., 1994; Foster et al., 1994; Shuin et al., 1994) and central nervous system hemangioblastomas (Kanno et al., 1994) provides evidence that these events are critical to the pathogenesis of such tumor types. This was further enhanced by the recent association of carcinogen exposure with specific VHL mutations in renal cell carcinoma (Brauch et al., 1999).
- Published
- 2000
37. Identification of extragenic suppressors of the cif1 mutation in Saccharomyces cerevisiae
- Author
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Blázquez, Miguel Ángel, Gancedo, Carlos, Blázquez, Miguel Ángel, and Gancedo, Carlos
- Abstract
The cif1 mutation of Saccharomyces cerevisiae causes inability to grow on glucose and related fermentable carbon sources. We have isolated two different suppressor mutations that allow growth on glucose of yeasts carrying the cif1 mutation. One of them, sci1-1, is recessive and caused inability to grow on non-fermentable carbon sources and to de-repress fructose-1,6-bisphosphatase. The other suppressor mutation, SCI2-1, is dominant and diminished the capacity to phosphorylate glucose or fructose. The SCT2-1 mutation decreased sporulation efficiency by 70% in heterozygosis and by more than 90% in homozygosis. In a CIF1 background, cells carrying the mutation SCI2-1 accumulated trehalose during the logarithmic phase of growth and hyperaccumulated it during the stationary phase. Genetic tests showed that SCI2 was either allelic, or else closely linked, to HXK2. The concentrations of the glycolytic metabolites measured during growth on glucose in cells carrying the cif1 mutation and any of the suppressor mutations were similar to those of a wild-type. Both types of suppresser mutations restored the transient cAMP response to glucose to cif1 mutants.
- Published
- 1994
38. The Role of Tumor Suppressor Genes in Ionizing Radiation-Induced Neoplastic Transformation of Human Epithelial Cells
- Author
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Dutta, Sujay, Dutta, Sujay, Dutta, Sujay, and Dutta, Sujay
- Published
- 1992
39. Amber suppressors of Erwinia chrysanthemi
- Author
-
Schoonejans, Eric F., Faelen, Michel, Desmet, Lucie, Toussaint, Ariane, Schoonejans, Eric F., Faelen, Michel, Desmet, Lucie, and Toussaint, Ariane
- Abstract
SCOPUS: ar.j, info:eu-repo/semantics/published
- Published
- 1987
40. Suppressing suppressors: Australia's prohibition of sound moderation in firearms
- Author
-
MacCarthy, Martin, O'Neill, Martin, Willson, Gregory B., MacCarthy, Martin, O'Neill, Martin, and Willson, Gregory B.
- Abstract
MacCarthy, M., O'Neill M., & Willson, G. (2016). Suppressing suppressors: Australia's prohibition of sound moderation in firearms. In proceedings of the Australian and New Zealand Marketing Academy Conference. (pp. 106-112) Christchurch, Australia. Available here
41. Suppressor Analysis Uncovers That MAPs and Microtubule Dynamics Balance with the Cut7/ Kinesin-5 Motor for Mitotic Spindle Assembly in Schizosaccharomyces pombe
- Author
-
Yukawa, Masashi, Yamada, Yusuke, Toda, Takashi, Yukawa, Masashi, Yamada, Yusuke, and Toda, Takashi
- Abstract
The Kinesin-5 motor Cut7 in Schizosaccharomyces pombe plays essential roles in spindle pole separation, leading to the assembly of bipolar spindle. In many organisms, simultaneous inactivation of Kinesin-14s neutralizes Kinesin-5 deficiency. To uncover the molecular network that counteracts Kinesin-5, we have conducted a genetic screening for suppressors that rescue the cut7-22 temperature sensitive mutation, and identified 10 loci. Next generation sequencing analysis reveals that causative mutations are mapped in genes encoding a-, b-tubulins and the microtubule plus-end tracking protein Mal3/EB1, in addition to the components of the Pkl1/Kinesin-14 complex. Moreover, the deletion of various genes required for microtubule nucleation/polymerization also suppresses the cut7 mutant. Intriguingly, Klp2/ Kinesin-14 levels on the spindles are significantly increased in cut7 mutants, whereas these increases are negated by suppressors, which may explain the suppression by these mutations/deletions. Consistent with this notion, mild overproduction of Klp2 in these double mutant cells confers temperature sensitivity. Surprisingly, treatment with a microtubule-destabilizing drug not only suppresses cut7 temperature sensitivity but also rescues the lethality resulting from the deletion of cut7, though a single klp2 deletion per se cannot compensate for the loss of Cut7. We propose that microtubule assembly and/or dynamics antagonize Cut7 functions, and that the orchestration between these two factors is crucial for bipolar spindle assembly., This work was supported by the Japan Society for the Promotion of Science (JSPS) [KAKENHI Scientific Research (A) (16H02503 to T.T.), a Challenging Exploratory Research grant (16K14672 to T.T.), Scientific Research (C) (16K07694 to M.Y.)], the Naito Foundation (T.T.) and the Uehara Memorial Foundation (T.T). M.Y. and T.T. designed research.M.Y. and Y.Y. performed experiments and analyzed the data.
42. B cell receptor signaling suppressor SHP-1 is active in CLL lymph node and peripheral blood
- Author
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Bergh, Ann-Charlotte, El-Schich, Zahra, Delfani, Payam, Ohlsson, Lars, Rosén, Anders, Gjörloff Wingren, Anette, Bergh, Ann-Charlotte, El-Schich, Zahra, Delfani, Payam, Ohlsson, Lars, Rosén, Anders, and Gjörloff Wingren, Anette
- Abstract
Protein tyrosine phosphatase SHP-1 expression and activity is downregulated or lost in several leukemias and lymphomas due to DNA promotor hypermethylation, catalytic site mutation or oxidation, or phosphorylation at inhibitory sites, implying a negative role of SHP-1 in development of leukemias/lymphomas. In chronic lymphocytic leukemia (CLL), B cell receptor (BcR) and microenvironment signal levels are important in the pathogenesis. Considering that SHP-1 is a BcR signaling suppressor, we hypothesized that SHP-1 would be down-regulated and/or inactivated in the proliferative center lymph node (LN) cells. We analyzed PTPN6 (SHP-1) gene expression, SHP-1 protein expression and phosphorylation status in matched CD5+/CD19+ peripheral blood (PB) and LN cells from 6 CLL patients, and in comparison, BcR (anti-IgM) in vitro triggered CLL PB cells from 10 patients. Gene expression of PTPN6 was significantly higher in PB compared to LN CLL cells in 50% of the cases. SHP-1 protein expression level and phosphorylation at SHP-1Y536 and SHP-1S591 were, however, equal in PB and LN samples. SHP-1 phosphorylation at Y536 and S591, in PB CLL cells cultured ex vivo was significantly reduced upon BcR engagement in all patient samples. These results indicate that in vivo BcR signaling in CLL is paralyzed.
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