14 results on '"Mei-Chong Wendy Lee"'
Search Results
2. A Novel Secreted Protein, MYR1, Is Central to Toxoplasma’s Manipulation of Host Cells
- Author
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Magdalena Franco, Michael W. Panas, Nicole D. Marino, Mei-Chong Wendy Lee, Kerry R. Buchholz, Felice D. Kelly, Jeffrey J. Bednarski, Barry P. Sleckman, Nader Pourmand, and John C. Boothroyd
- Subjects
Microbiology ,QR1-502 - Abstract
ABSTRACT The intracellular protozoan Toxoplasma gondii dramatically reprograms the transcriptome of host cells it infects, including substantially up-regulating the host oncogene c-myc. By applying a flow cytometry-based selection to infected mouse cells expressing green fluorescent protein fused to c-Myc (c-Myc–GFP), we isolated mutant tachyzoites defective in this host c-Myc up-regulation. Whole-genome sequencing of three such mutants led to the identification of MYR1 (Myc regulation 1; TGGT1_254470) as essential for c-Myc induction. MYR1 is a secreted protein that requires TgASP5 to be cleaved into two stable portions, both of which are ultimately found within the parasitophorous vacuole and at the parasitophorous vacuole membrane. Deletion of MYR1 revealed that in addition to its requirement for c-Myc up-regulation, the MYR1 protein is needed for the ability of Toxoplasma tachyzoites to modulate several other important host pathways, including those mediated by the dense granule effectors GRA16 and GRA24. This result, combined with its location at the parasitophorous vacuole membrane, suggested that MYR1 might be a component of the machinery that translocates Toxoplasma effectors from the parasitophorous vacuole into the host cytosol. Support for this possibility was obtained by showing that transit of GRA24 to the host nucleus is indeed MYR1-dependent. As predicted by this pleiotropic phenotype, parasites deficient in MYR1 were found to be severely attenuated in a mouse model of infection. We conclude, therefore, that MYR1 is a novel protein that plays a critical role in how Toxoplasma delivers effector proteins to the infected host cell and that this is crucial to virulence. IMPORTANCE Toxoplasma gondii is an important human pathogen and a model for the study of intracellular parasitism. Infection of the host cell with Toxoplasma tachyzoites involves the introduction of protein effectors, including many that are initially secreted into the parasitophorous vacuole but must ultimately translocate to the host cell cytosol to function. The work reported here identified a novel protein that is required for this translocation. These results give new insight into a very unusual cell biology process as well as providing a potential handle on a pathway that is necessary for virulence and, therefore, a new potential target for chemotherapy.
- Published
- 2016
- Full Text
- View/download PDF
3. In search of an uncultured human-associated TM7 bacterium in the environment.
- Author
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Jorge M Dinis, David E Barton, Jamsheed Ghadiri, Deepa Surendar, Kavitha Reddy, Fernando Velasquez, Carol L Chaffee, Mei-Chong Wendy Lee, Helen Gavrilova, Hazel Ozuna, Samuel A Smits, and Cleber C Ouverney
- Subjects
Medicine ,Science - Abstract
We have identified an environmental bacterium in the Candidate Division TM7 with ≥98.5% 16S rDNA gene homology to a group of TM7 bacteria associated with the human oral cavity and skin. The environmental TM7 bacterium (referred to as TM7a-like) was readily detectable in wastewater with molecular techniques over two years of sampling. We present the first images of TM7a-like cells through FISH technique and the first images of any TM7 as viable cells through the STARFISH technique. In situ quantification showed TM7 concentration in wastewater up to five times greater than in human oral sites. We speculate that upon further characterization of the physiology and genetics of the TM7a-like bacterium from environmental sources and confirmation of its genomic identity to human-associated counterparts it will serve as model organisms to better understand its role in human health. The approach proposed circumvents difficulties imposed by sampling humans, provides an alternative strategy to characterizing some diseases of unknown etiology, and renders a much needed understanding of the ecophysiological role hundreds of unique Bacteria and Archaea strains play in mixed microbial communities.
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- 2011
- Full Text
- View/download PDF
4. Whole genome sequencing data of multiple individuals of Pakistani descent
- Author
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Shahid Y. Khan, Muhammad Ali, Sheikh Riazuddin, Mei-Chong Wendy Lee, J. Fielding Hejtmancik, Radha Ayyagari, Muhammad Asif Naeem, Saima Riazuddin, S. Amer Riazuddin, Zhiwei Ma, Asma A. Khan, and Pooja Biswas
- Subjects
Statistics and Probability ,Data Descriptor ,Single-nucleotide polymorphism ,Library and Information Sciences ,Biology ,Polymorphism, Single Nucleotide ,Genome ,Haplogroup ,Education ,03 medical and health sciences ,0302 clinical medicine ,Intergenic region ,Genotype ,Genetics ,Humans ,SNP ,Pakistan ,Polymorphism ,1000 Genomes Project ,lcsh:Science ,030304 developmental biology ,Whole genome sequencing ,0303 health sciences ,Whole Genome Sequencing ,Genome, Human ,Comparative genomics ,Human Genome ,Single Nucleotide ,Computer Science Applications ,Next-generation sequencing ,lcsh:Q ,Statistics, Probability and Uncertainty ,030217 neurology & neurosurgery ,Human ,Information Systems - Abstract
Here we report whole genome sequencing of four individuals (H3, H4, H5, and H6) from a family of Pakistani descent. Whole genome sequencing yielded 1084.92, 894.73, 1068.62, and 1005.77 million mapped reads corresponding to 162.73, 134.21, 160.29, and 150.86 Gb sequence data and 52.49x, 43.29x, 51.70x, and 48.66x average coverage for H3, H4, H5, and H6, respectively. We identified 3,529,659, 3,478,495, 3,407,895, and 3,426,862 variants in the genomes of H3, H4, H5, and H6, respectively, including 1,668,024 variants common in the four genomes. Further, we identified 42,422, 39,824, 28,599, and 35,206 novel variants in the genomes of H3, H4, H5, and H6, respectively. A major fraction of the variants identified in the four genomes reside within the intergenic regions of the genome. Single nucleotide polymorphism (SNP) genotype based comparative analysis with ethnic populations of 1000 Genomes database linked the ancestry of all four genomes with the South Asian populations, which was further supported by mitochondria based haplogroup analysis. In conclusion, we report whole genome sequencing of four individuals of Pakistani descent., Measurement(s) SNV • genome Technology Type(s) whole genome sequencing • DNA sequencing Factor Type(s) individual Sample Characteristic - Organism Homo sapiens Sample Characteristic - Location Pakistan Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12642761
- Published
- 2020
- Full Text
- View/download PDF
5. Identification of novel transcripts and peptides in developing murine lens
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Sean F. Hackett, S. Amer Riazuddin, Firoz Kabir, Muhammad Ali, Mei-Chong Wendy Lee, Ruiqiang Chen, Nader Pourmand, Chan Hyun Na, and Shahid Y. Khan
- Subjects
0301 basic medicine ,Proteome ,Organogenesis ,lcsh:Medicine ,Transcriptome ,Exon ,Lens ,Mice ,Pregnancy ,Tandem Mass Spectrometry ,Databases, Genetic ,2.1 Biological and endogenous factors ,Aetiology ,lcsh:Science ,Pediatric ,Chromatography ,Liquid ,Multidisciplinary ,High-Throughput Nucleotide Sequencing ,Exons ,RNA splicing ,Female ,Sequence Analysis ,Algorithms ,Biotechnology ,Sequence analysis ,Computational biology ,Biology ,Article ,03 medical and health sciences ,Databases ,Genetic ,Lens, Crystalline ,Genetics ,Animals ,Eye Disease and Disorders of Vision ,Crystalline ,Sequence Analysis, RNA ,Alternative splicing ,lcsh:R ,Intron ,Exon skipping ,Introns ,Alternative Splicing ,030104 developmental biology ,RNA ,lcsh:Q ,RNA Splice Sites ,Peptides ,Chromatography, Liquid - Abstract
We previously investigated the transcriptome and proteome profiles of the murine ocular lens at six developmental time points including two embryonic (E15 and E18) and four postnatal time points (P0, P3, P6, and P9). Here, we extend our analyses to identify novel transcripts and peptides in developing mouse lens. We identified a total of 9,707 novel transcripts and 325 novel fusion genes in developing mouse lens. Additionally, we identified 13,281 novel alternative splicing (AS) events in mouse lens including 6,990 exon skipping (ES), 2,447 alternative 3′ splice site (A3SS), 1,900 alternative 5′ splice site (A5SS), 1,771 mutually exclusive exons (MXE), and 173 intron retention (IR). Finally, we integrated our OMIC (Transcriptome and Proteome) datasets identifying 20 novel peptides in mouse lens. All 20 peptides were validated through matching MS/MS spectra of synthetic peptides. To the best of our knowledge, this is the first report integrating OMIC datasets to identify novel peptides in developing murine lens.
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- 2018
- Full Text
- View/download PDF
6. The role of dinB in UV survival and UV-induced mutagenesis in Escherichia coli
- Author
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Mei-Chong Wendy Lee
- Published
- 2019
- Full Text
- View/download PDF
7. Erratum for Franco et al., 'A Novel Secreted Protein, MYR1, Is Central to Toxoplasma ’s Manipulation of Host Cells'
- Author
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Mei-Chong Wendy Lee, Magdalena Franco, Jeffrey J. Bednarski, Michael W. Panas, Felice D. Kelly, Barry P. Sleckman, Nicole D. Marino, Kerry R. Buchholz, Nader Pourmand, and John C. Boothroyd
- Subjects
Mutation ,Virulence Factors ,Host (biology) ,Macrophages ,Sequencing data ,Protozoan Proteins ,Biology ,medicine.disease_cause ,Microbiology ,Molecular biology ,QR1-502 ,Mice ,Toxoplasmosis, Animal ,Virology ,Host-Pathogen Interactions ,medicine ,Animals ,Erratum ,Toxoplasma ,Gene ,Gene Deletion ,Research Article - Abstract
The intracellular protozoan Toxoplasma gondii dramatically reprograms the transcriptome of host cells it infects, including substantially up-regulating the host oncogene c-myc. By applying a flow cytometry-based selection to infected mouse cells expressing green fluorescent protein fused to c-Myc (c-Myc–GFP), we isolated mutant tachyzoites defective in this host c-Myc up-regulation. Whole-genome sequencing of three such mutants led to the identification of MYR1 (Myc regulation 1; TGGT1_254470) as essential for c-Myc induction. MYR1 is a secreted protein that requires TgASP5 to be cleaved into two stable portions, both of which are ultimately found within the parasitophorous vacuole and at the parasitophorous vacuole membrane. Deletion of MYR1 revealed that in addition to its requirement for c-Myc up-regulation, the MYR1 protein is needed for the ability of Toxoplasma tachyzoites to modulate several other important host pathways, including those mediated by the dense granule effectors GRA16 and GRA24. This result, combined with its location at the parasitophorous vacuole membrane, suggested that MYR1 might be a component of the machinery that translocates Toxoplasma effectors from the parasitophorous vacuole into the host cytosol. Support for this possibility was obtained by showing that transit of GRA24 to the host nucleus is indeed MYR1-dependent. As predicted by this pleiotropic phenotype, parasites deficient in MYR1 were found to be severely attenuated in a mouse model of infection. We conclude, therefore, that MYR1 is a novel protein that plays a critical role in how Toxoplasma delivers effector proteins to the infected host cell and that this is crucial to virulence., IMPORTANCE Toxoplasma gondii is an important human pathogen and a model for the study of intracellular parasitism. Infection of the host cell with Toxoplasma tachyzoites involves the introduction of protein effectors, including many that are initially secreted into the parasitophorous vacuole but must ultimately translocate to the host cell cytosol to function. The work reported here identified a novel protein that is required for this translocation. These results give new insight into a very unusual cell biology process as well as providing a potential handle on a pathway that is necessary for virulence and, therefore, a new potential target for chemotherapy.
- Published
- 2018
- Full Text
- View/download PDF
8. A ΔdinB mutation that sensitizes Escherichia coli to the lethal effects of UV- and X-radiation
- Author
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Robert G. Fowler, Magdalena Franco, Steven J. White, Deborah A Hudman, Neil J. Sargentini, Mei-Chong Wendy Lee, and Doris M. Vargas
- Subjects
Ultraviolet Rays ,Health, Toxicology and Mutagenesis ,Mutant ,DNA-Directed DNA Polymerase ,Biology ,medicine.disease_cause ,Article ,Radiation sensitivity ,Escherichia coli ,Genetics ,medicine ,Allele ,Molecular Biology ,Alleles ,Adenosine Triphosphatases ,chemistry.chemical_classification ,Mutation ,Microbial Viability ,Strain (chemistry) ,Escherichia coli Proteins ,X-Rays ,DNA Helicases ,G2-M DNA damage checkpoint ,Molecular biology ,Amino acid ,DNA-Binding Proteins ,chemistry - Abstract
The DinB (PolIV) protein of Escherichia coli participates in several cellular functions. We investigated a dinB mutation, Δ(dinB-yafN)883(::kan) [referred to as ΔdinB883], which strongly sensitized E. coli cells to both UV- and X-radiation killing. Earlier reports indicated dinB mutations had no obvious effect on UV radiation sensitivity which we confirmed by showing that normal UV radiation sensitivity is conferred by the ΔdinB749 allele. Compared to a wild-type strain, the ΔdinB883 mutant was most sensitive (160-fold) in early to mid-logarithmic growth phase and much less sensitive (twofold) in late log or stationary phases, thus showing a growth phase-dependence for UV radiation sensitivity. This sensitizing effect of ΔdinB883 is assumed to be completely dependent upon the presence of UmuDC protein; since the ΔdinB883 mutation did not sensitize the ΔumuDC strain to UV radiation killing throughout log phase and early stationary phase growth. The DNA damage checkpoint activity of UmuDC was clearly affected by ΔdinB883 as shown by testing a umuC104 ΔdinB883 double-mutant. The sensitivities of the ΔumuDC strain and the ΔdinB883 ΔumuDC double-mutant strain were significantly greater than for the ΔdinB883 strain, suggesting that the ΔdinB883 allele only partially suppresses UmuDC activity. The ΔdinB883 mutation partially sensitized (fivefold) uvrA and uvrB strains to UV radiation, but did not sensitize a ΔrecA strain. A comparison of the DNA sequences of the ΔdinB883 allele with the sequences of the Δ(dinB-yafN)882(::kan) and ΔdinB749 alleles, which do not sensitize cells to UV radiation, revealed ΔdinB883 is likely a "gain-of-function" mutation. The ΔdinB883 allele encodes the first 54 amino acids of wild-type DinB followed by 29 predicted residues resulting from the continuation of the dinB reading frame into an adjacent insertion fragment. The resulting polypeptide is proposed to interfere directly or indirectly with UmuDC function(s) involved in protecting cells against the lethal effects of radiation.
- Published
- 2014
- Full Text
- View/download PDF
9. FOXE3 contributes to Peters anomaly through transcriptional regulation of an autophagy-associated protein termed DNAJB1
- Author
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Julie Laux, Shivakumar Vasanth, Zhiwei Ma, Carmen C. Leitch, Rafael Villasmil, S. Amer Riazuddin, Robert N. Cole, Shaheen N. Khan, C. Conover Talbot, Javed Akram, Nader Pourmand, Mei-Chong Wendy Lee, J. Fielding Hejtmancik, Firoz Kabir, Norann A. Zaghloul, Raghothama Chaerkady, Shahid Y. Khan, Arif O. Khan, John D. Gottsch, and Sheikh Riazuddin
- Subjects
0301 basic medicine ,Male ,Morpholino ,Science ,General Physics and Astronomy ,Whole Exome Sequencing ,General Biochemistry, Genetics and Molecular Biology ,Article ,Transcriptome ,Lens ,03 medical and health sciences ,Corneal Opacity ,MD Multidisciplinary ,Lens, Crystalline ,Exome Sequencing ,Genetics ,Transcriptional regulation ,Autophagy ,2.1 Biological and endogenous factors ,Animals ,Humans ,Eye Abnormalities ,Aetiology ,Eye Disease and Disorders of Vision ,Transcription factor ,Zebrafish ,Regulation of gene expression ,Family Health ,Gene knockdown ,Multidisciplinary ,Crystalline ,biology ,Gene Expression Profiling ,Epithelial Cells ,Forkhead Transcription Factors ,General Chemistry ,HSP40 Heat-Shock Proteins ,biology.organism_classification ,Molecular biology ,Pedigree ,030104 developmental biology ,HEK293 Cells ,Gene Expression Regulation ,Gene Knockdown Techniques ,Female ,Chromatin immunoprecipitation - Abstract
FOXE3 is a lens-specific transcription factor that has been associated with anterior segment ocular dysgenesis. To determine the transcriptional target(s) of FOXE3 that are indispensable for the anterior segment development, we examined the transcriptome and the proteome of cells expressing truncated FOXE3 responsible for Peters anomaly identified through linkage-coupled next-generation whole-exome sequencing. We found that DNAJB1, an autophagy-associated protein, was the only candidate exhibiting differential expression in both screens. We confirmed the candidacy of DNAJB1 through chromatin immunoprecipitation and luciferase assays while knockdown of DNAJB1 in human lens epithelial cells resulted in a mitotic arrest. Subsequently, we targeted dnajb1a in zebrafish through injection of a splice-blocking morpholino. The dnajb1a morphants exhibited underdeveloped cataractous lenses with persistent apoptotic nuclei. In conclusion, here we report DNAJB1 is a transcriptional target of FOXE3 in a novel pathway that is crucial for the development of the anterior segment of the eye., Peter's Anomaly is a developmental disorder of the eye and has been linked to mutations in a range of genes, including the transcription factor FOXE3. Here the authors use next-generation RNA sequencing and mass spectrometry to identify an autophagy-associated protein, DNAJB1 as the transcriptional target of FOXE3.
- Published
- 2016
10. A Novel Secreted Protein, MYR1, Is Central to Toxoplasma’s Manipulation of Host Cells
- Author
-
John C. Boothroyd, Michael W. Panas, Barry P. Sleckman, Kerry R. Buchholz, Magdalena Franco, Nader Pourmand, Jeffrey J. Bednarski, Nicole D. Marino, Mei-Chong Wendy Lee, and Felice D. Kelly
- Subjects
0301 basic medicine ,Host cell cytosol ,biology ,Effector ,Mutant ,Virulence ,Toxoplasma gondii ,biology.organism_classification ,Microbiology ,QR1-502 ,3. Good health ,Green fluorescent protein ,Cell biology ,Transcriptome ,03 medical and health sciences ,030104 developmental biology ,Virology ,Intracellular - Abstract
The intracellular protozoan Toxoplasma gondii dramatically reprograms the transcriptome of host cells it infects, including substantially up-regulating the host oncogene c -myc . By applying a flow cytometry-based selection to infected mouse cells expressing green fluorescent protein fused to c-Myc (c-Myc–GFP), we isolated mutant tachyzoites defective in this host c-Myc up-regulation. Whole-genome sequencing of three such mutants led to the identification of MYR1 ( My c r egulation 1 ; TGGT1_254470 ) as essential for c-Myc induction. MYR1 is a secreted protein that requires TgASP5 to be cleaved into two stable portions, both of which are ultimately found within the parasitophorous vacuole and at the parasitophorous vacuole membrane. Deletion of MYR1 revealed that in addition to its requirement for c-Myc up-regulation, the MYR1 protein is needed for the ability of Toxoplasma tachyzoites to modulate several other important host pathways, including those mediated by the dense granule effectors GRA16 and GRA24. This result, combined with its location at the parasitophorous vacuole membrane, suggested that MYR1 might be a component of the machinery that translocates Toxoplasma effectors from the parasitophorous vacuole into the host cytosol. Support for this possibility was obtained by showing that transit of GRA24 to the host nucleus is indeed MYR1-dependent. As predicted by this pleiotropic phenotype, parasites deficient in MYR1 were found to be severely attenuated in a mouse model of infection. We conclude, therefore, that MYR1 is a novel protein that plays a critical role in how Toxoplasma delivers effector proteins to the infected host cell and that this is crucial to virulence. IMPORTANCE Toxoplasma gondii is an important human pathogen and a model for the study of intracellular parasitism. Infection of the host cell with Toxoplasma tachyzoites involves the introduction of protein effectors, including many that are initially secreted into the parasitophorous vacuole but must ultimately translocate to the host cell cytosol to function. The work reported here identified a novel protein that is required for this translocation. These results give new insight into a very unusual cell biology process as well as providing a potential handle on a pathway that is necessary for virulence and, therefore, a new potential target for chemotherapy.
- Published
- 2016
11. Abstract 1518: Lung adenocarcinoma differential expression analysis using the Maverix RNA-Seq pipeline
- Author
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Lenin Subramanian, Mei-Chong Wendy Lee, Byung-In Lee, and Michael S. Fitzsimons
- Subjects
Cancer Research ,Differential expression analysis ,Computer science ,Pipeline (computing) ,RNA-Seq ,Computational biology ,medicine.disease ,Differentially expressed genes ,Oncology ,medicine ,Adenocarcinoma ,Completion time ,Differential expression ,Analysis tools - Abstract
Background RNA-Seq is a powerful means of identifying changes in gene expression in cancerous tissue. Widespread adoption of RNA-Seq is hampered by lack of familiarity with the appropriate analysis tools and excessive turn around time. Maverix Biomics, Inc offers a scalable, reliable, validated, and easily accessible differential expression pipeline for translational and clinical researchers to analyze and explore RNA-Seq data. Here we describe the pipeline, demonstrate the available tools and visualizations, and provide benchmarks for completion time from lung adenocarcinoma. Results Lung adenocarcinoma samples appear very different compared to their normal counterparts in terms of overall gene expression and exhibit many differentially expressed genes. For analysis completion time, parallelization is far superior than the theoretical curve without parallelization. It took 7.9 hours to analyze two samples, but took only 13.1 hours to analyze 25 samples. We found 2246 significant genes common to three different differential expression tools: DESeq, edgeR, and cuffdiff. Conclusions The Maverix RNA-Seq pipeline is demonstrated here to be highly scalable, easy to use, and includes a range of tools and visualizations for understanding differential expressions results. This pipeline is a great analytic option to accelerate translational and clinical research in the field of oncology. Citation Format: Michael S. Fitzsimons, Mei-Chong Wendy Lee, Byung-In Lee, Lenin Subramanian. Lung adenocarcinoma differential expression analysis using the Maverix RNA-Seq pipeline. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1518.
- Published
- 2016
- Full Text
- View/download PDF
12. In search of an uncultured human-associated TM7 bacterium in the environment
- Author
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Fernando Velasquez, Samuel A. Smits, Kavitha Reddy, Cleber C. Ouverney, Carol L. Chaffee, Jorge M. Dinis, Mei-Chong Wendy Lee, Deepa Surendar, Helen Gavrilova, Jamsheed Ghadiri, Hazel Ozuna, and David Barton
- Subjects
Applied Microbiology ,ved/biology.organism_classification_rank.species ,lcsh:Medicine ,Polymerase Chain Reaction ,law.invention ,law ,RNA, Ribosomal, 16S ,lcsh:Science ,Polymerase chain reaction ,In Situ Hybridization, Fluorescence ,Phylogeny ,Genetics ,0303 health sciences ,Multidisciplinary ,biology ,6. Clean water ,Bacterial Pathogens ,Host-Pathogen Interaction ,Infectious Diseases ,Medical Microbiology ,Prokaryotic Models ,Medicine ,Gene homology ,Water Microbiology ,Research Article ,Candidate division TM7 ,Microbiology ,Microbial Ecology ,03 medical and health sciences ,Model Organisms ,Humans ,Model organism ,Biology ,Microbial Pathogens ,030304 developmental biology ,Cloning ,Mouth ,Bacterial Evolution ,Bacteria ,030306 microbiology ,ved/biology ,lcsh:R ,Bacteriology ,16S ribosomal RNA ,biology.organism_classification ,Emerging Infectious Diseases ,Microscopy, Fluorescence ,lcsh:Q ,Archaea - Abstract
We have identified an environmental bacterium in the Candidate Division TM7 with ≥98.5% 16S rDNA gene homology to a group of TM7 bacteria associated with the human oral cavity and skin. The environmental TM7 bacterium (referred to as TM7a-like) was readily detectable in wastewater with molecular techniques over two years of sampling. We present the first images of TM7a-like cells through FISH technique and the first images of any TM7 as viable cells through the STARFISH technique. In situ quantification showed TM7 concentration in wastewater up to five times greater than in human oral sites. We speculate that upon further characterization of the physiology and genetics of the TM7a-like bacterium from environmental sources and confirmation of its genomic identity to human-associated counterparts it will serve as model organisms to better understand its role in human health. The approach proposed circumvents difficulties imposed by sampling humans, provides an alternative strategy to characterizing some diseases of unknown etiology, and renders a much needed understanding of the ecophysiological role hundreds of unique Bacteria and Archaea strains play in mixed microbial communities.
- Published
- 2011
13. Abstract A09: Single-cell RNA sequencing reveals phenotypic plasticity of drug tolerant, clonal populations of cancer cells
- Author
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Mei-Chong Wendy Lee, Muhammad Tariq, Charles J. Vaske, Yelena Dayn, Shahid Y. Khan, Nader Pourmand, Fernando J. Lopez-Diaz, and Beverly M. Emerson
- Subjects
Genetics ,Cancer Research ,education.field_of_study ,Population ,Cell ,Biology ,Suicide gene ,medicine.anatomical_structure ,Oncology ,Cancer stem cell ,Cancer cell ,Gene expression ,Cancer research ,medicine ,Progenitor cell ,education ,Gene - Abstract
Cancer recurrence and metastatic tumors might arise not only from residual primary tumor cells but even from precancerous cells that are able to spread and seed distant organs. Thus, residual pre-neoplastic and neoplastic cells that persist following treatment constitute an ideal evolutionary niche for cancer evolution. We have investigated the role of the TGF-beta; signaling pathway, which is widely known as a pro-metastatic in late stages of tumor progression, in the context of the cellular response to genotoxic stress induced by chemotherapy drugs. We identified that TGF-beta signaling contribute to drug resistance by repressing the DNA damage response through a coordinate repression of transcription and translation of p53 and the stress response in precancerous and cancer cells. Indeed, TGF-beta/Smad signaling enacts an intrinsic survival pathway in metastatic cancer cells. However, the molecular events accompanying the evolution towards a drug tolerant phenotype are not well understood. Indeed, severe cellular stress might generate or select a subpopulation of reversibly stress-tolerant cells under conditions that are lethal to the majority of the population. Thus, drug tolerance could be attributed to heterogeneity of gene expression within the population to ensure survival of a minority under stress. To address these questions, we developed an experimental paradigm to generate and propagate populations of paclitaxel tolerant precancerous (MCF10A) and metastatic cancer (MDA-MB-231) cells that can resume proliferation after 1 week of consecutive treatment with lethal doses of the drug. We found that drug-tolerant cells reacquired Paclitaxel-sensitivity after expansion. Then we performed whole transcriptome sequencing to identify single nucleotide variants (SNVs) and gene expression profiles at the single-cell level associated with the evolution towards a reversible drug tolerant state in cancer cells. We evaluated untreated, stress-arrested and proliferating drug-tolerant cells from a small (n We find that within untreated, stress-arrested and drug-tolerant cell groups, specific transcriptional programs were enacted while generating high heterogeneity between single cells within and between groups. Drug-tolerant cells contained specific RNA variants encoded by genes involved in microtubule organization and stabilization as well as cell adhesion and cell surface signaling. Unexpectedly, Drug-tolerant cells from a single progenitor cell rapidly reacquired high degree of heterogeneity in gene expression similar to untreated cells, within a few doublings, while uniquely expressing SNVs and genes such as Integrin alpha 6, the histone demethylase KDM5A, and the IGF-1 receptor. Interestingly, despite of the high degree of heterogeneity, the whole gene expression profiles, of each cell rather than small gene sets can identify the response of cells to taxol. Thus, single cell analyses reveal the dynamics of the response to stress in terms of cell-specific SNVs driving heterogeneity, the survival of a minority population through generation of specific genes and RNA variants and the efficient reconversion of drug-tolerant cells back to normalcy, suggesting that such heterogeneity within cancer cell populations might provide evolutionary advantage to increase the pool of drug tolerant cells poising a prospective path towards drug resistance. Citation Format: Fernando Lopez-Diaz, Mei-Chong Wendy Lee, Muhammad Tariq, Shahid Khan, Yelena Dayn, Charlie Vaske, Nader Pourmand, Beverly M. Emerson. Single-cell RNA sequencing reveals phenotypic plasticity of drug tolerant, clonal populations of cancer cells. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr A09.
- Published
- 2015
- Full Text
- View/download PDF
14. Abstract PR05: Single-cell RNA sequencing reveals phenotypic plasticity of drug tolerant clonal populations of cancer cells
- Author
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Muhammad Tariq, Charles J. Vaske, Nader Pourmand, Shahid Y. Khan, Mei-Chong Wendy Lee, Yelena Dayn, Beverly M. Emerson, and Fernando J. Lopez-Diaz
- Subjects
Genetics ,Cancer Research ,education.field_of_study ,Population ,Cell ,Biology ,Gene expression profiling ,medicine.anatomical_structure ,Oncology ,Gene expression ,Cancer cell ,medicine ,Cytotoxic T cell ,Progenitor cell ,education ,Gene - Abstract
The notion that most cancers are ecosystems of evolving clones is now widely accepted. Hence, residual neoplastic cells that persist following treatment constitute an ideal evolutionary niche from which recurrent cancers arise and are a major obstacle to the successful treatment of human cancers. We have identified that TGFβ signaling contribute to drug resistance by coordinately repressing transcription and translation of p53 in precancerous and cancer cells. However, the molecular events accompanying the evolution towards a drug tolerant phenotype are not well understood. Indeed, severe cellular stress might generate a subpopulation of reversibly stress-tolerant cells under conditions that are lethal to the majority of the population. Drug tolerance attributed to heterogeneity of gene expression within the population to ensure survival of a minority under stress. To address these questions, we developed an experimental paradigm to generate and propagate populations of paclitaxel tolerant precancerous (MCF10A) and metastatic cancer (MDA-MB-231) cells that can resume proliferation after 1 week of consecutive treatment with lethal doses of the drug . We found that drug-tolerant cells reacquired Paclitaxel-sensitivity after expansion. Then we performed whole transcriptome sequencing to identify single nucleotide variants (SNVs) and gene expression profiles at the single-cell level associated with the evolution towards a reversible drug tolerant state in cancer cells. We evaluated untreated, stress-arrested and proliferating drug-tolerant cells from a small (n We find that within untreated, stress-arrested and drug-tolerant cell groups, specific transcriptional programs were enacted while generating high heterogeneity between single cells within and between groups. Drug-tolerant cells contained specific RNA variants encoded by genes involved in microtubule organization and stabilization as well as cell adhesion and cell surface signaling. Unexpectedly, Drug-tolerant cells from a single progenitor cell rapidly reacquired high degree of heterogeneity in gene expression similar to untreated cells, within a few doublings, while uniquely expressing SNVs and genes such as Integrin alpha 6, the histone demethylase KDM5A, and the IGF-1 receptor. Thus, single cell analyses reveal the dynamics of the response to stress in terms of cell-specific SNVs driving heterogeneity, the survival of a minority population through generation of specific genes and RNA variants and the efficient reconversion of drug-tolerant cells back to normalcy, suggesting that such heterogeneity within cancer cell populations might provide evolutionary advantage to increase the pool of drug tolerant cells poising a prospective path towards drug resistance. This abstract is also presented as poster B68. Citation Format: Fernando J. Lopez-Diaz, Mei-Chong Wendy Lee, Muhammad A. Tariq, Yelena Dayn, Shahid Y. Khan, Charlie Vaske, Nader Pourmand, Beverly M. Emerson. Single-cell RNA sequencing reveals phenotypic plasticity of drug tolerant clonal populations of cancer cells. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr PR05.
- Published
- 2013
- Full Text
- View/download PDF
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