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Vitamin C induces Tet-dependent DNA demethylation and a blastocyst-like state in ES cells.
Specimen part, Treatment, Time
View SamplesDNA methylation is a heritable epigenetic modification involved in gene silencing, imprinting, and the suppression of retrotransposons. Global DNA demethylation occurs in the early embryo and the germline and may be mediated by Tet (ten-eleven-translocation) enzymes, which convert 5-methylcytosine (mC) to 5-hydroxymethylcytosine (hmC). Tet enzymes have been extensively studied in mouse embryonic stem (ES) cells, which are generally cultured in the absence of Vitamin C, a potential co-factor for Fe(II) 2-oxoglutarate dioxygenase enzymes like Tets. Here we report that addition of Vitamin C to ES cells promotes Tet activity leading to a rapid and global increase in hmC. This is followed by DNA demethylation of numerous gene promoters and up-regulation of demethylated germline genes. Tet1 binding is enriched near the transcription start site (TSS) of genes affected by Vitamin C treatment. Importantly, Vitamin C, but not other antioxidants, enhances the activity of recombinant human Tet1 in a biochemical assay and the Vitamin C-induced changes in hmC and mC are entirely suppressed in Tet1/2 double knockout (Tet DKO) ES cells. Vitamin C has the strongest effects on regions that gain methylation in cultured ES cells compared to blastocysts and in vivo are methylated only after implantation. In contrast, imprinted regions and intracisternal A-particle (IAP) elements, which are resistant to demethylation in the early embryo, are resistant to Vitamin C-induced DNA demethylation. Collectively, this study establishes that Vitamin C is a direct regulator of Tet activity and DNA methylation fidelity in ES cells.
Vitamin C induces Tet-dependent DNA demethylation and a blastocyst-like state in ES cells.
Specimen part
View SamplesAHI-1 is an oncogene often targeted by provirus insertional mutagenesis in murine leukemias and lymphomas. Aberrant expression of human AHI-1 occurs in cutaneous T-cell lymphoma (CTCL) cells and in CD4+CD7- Sezary cells from patients with Sezary syndrome (SS). Stable knockdown of AHI-1 using retroviral-mediated RNA interference in CTCL cells inhibits their transforming activity in vitro and in vivo. To identify genes involved in AHI-1-mediated transformation, microarray analysis was performed to identify differentially expressed genes in AHI-1 suppressed CTCL cells. Fifteen up-regulated and six down-regulated genes were identified and confirmed by Q-RT-PCR. Seven were further confirmed in a microarray analysis of CD4+CD7- Sezary cells from SS patients. HCK and BIN1 emerged as new candidate cooperative genes, with differential protein expression which correlates with observed transcript changes. Interestingly, changes in HCK phosphorylation and biological response to its inhibitor, dasatinib, were observed in AHI-1 suppressed or overexpressed cells. The tumor suppressor BIN1 physically interacts with MYC in CTCL cells, which also exhibit differential MYC protein expression. In addition, aberrant expression of alternative splicing forms of BIN1 was observed in primary and transformed CTCL cells. These findings indicate that HCK and BIN1 may play critical roles in AHI-1-mediated leukemic transformation of human CTCL cells.
Identification of tyrosine kinase, HCK, and tumor suppressor, BIN1, as potential mediators of AHI-1 oncogene in primary and transformed CTCL cells.
No sample metadata fields
View SamplesBy screening for genes possessing canonical X-box sequences in promoters of three Caenorhabditis species, namely C. elegans, C. briggsae and C. remanei, we identified 93 genes (including known X-box regulated genes) that encode putative components of ciliated neurons in C. elegans and are subject to the same regulatory control. For many of these genes, restricted anatomical expression in ciliated cells was confirmed, and control of transcription by the ciliogenic DAF-19 RFX transcription factor was demonstrated by comparative transcriptional profiling of daf-19(+) and daf-19(-) animals.
Identification of ciliary and ciliopathy genes in Caenorhabditis elegans through comparative genomics.
No sample metadata fields
View SamplesPKR is an interferon induced serine/threonine protein kinase, that is activated by double stranded RNA. PKR plays an important role in the antiviral defense by interferon. In addition to its role in translation, PKR participates in several signaling pathways to transcription. The goal of this experiment is to study the role of PKR in regulating gene expression in our NIH 3T3 inducible cell line, which could overexpress PKR wt protein after the removal of tetracycline (Donze O, Dostie J, Sonenberg N. (1999) Virology 256: 322-9).
The protein kinase PKR: a molecular clock that sequentially activates survival and death programs.
Cell line
View SamplesWildtype B6, Rag1-/- B6 and Rag1-/- B6 mice harboring the 225.4 IgA producing hybridoma were colonized for 10 days with Bacteroides thetaiotaomicron
IgA response to symbiotic bacteria as a mediator of gut homeostasis.
No sample metadata fields
View SamplesIt has generally been assumed that most differences between males and females are due to developmental and hormonal differences between the sexes. Here we investigate the contribution of sex chromosomal complement to such sexual dimorphisms. These genome-wide transcription profiling showed that the expression of hundreds of autosomal genes was sensitive to sex chromosome complement, rather than gender. The existence of such differences between males and females holds important implications for understanding sexual dimorphisms in physiology and disease hitherto attributed solely to gender or hormonal effects.
No associated publication
Sex, Specimen part
View SamplesDiagnosis of acute respiratory viral infection is currentlybased on clinical symptoms and pathogen detection. Use of host peripheral blood gene expression data to classify individuals with viral respiratory infection represents a novel means of infection diagnosis.
Gene expression signatures diagnose influenza and other symptomatic respiratory viral infections in humans.
Subject, Time
View SamplesOsteoblasts are key players in bone remodeling. The accessibility of human primary osteoblast-like cells (HOb) from bone explants render them a lucrative model for studying molecular physiology of bone turnover, discovery of novel anabolic therapeutics and mesenchymal cell biology in general. Relatively little is known about resting and dynamic expression profiles of HObs and no studies have been conducted to date to systematically assess the osteoblast transcriptome. The aim of this study was to characterize HObs and investigate signaling cascades and gene networks using genomewide expression profiling in resting and Bone Morphogenic Protein (BMP)-2 and Dexamethasone induced cells.
Systematic assessment of the human osteoblast transcriptome in resting and induced primary cells.
No sample metadata fields
View SamplesTransgenic (Probasin driven Myr-AKT)or wild-type littermates were treated with RAD001 or placebo and sacrificed at 12 and 48 hours following the beginning of treatment
mTOR inhibition reverses Akt-dependent prostate intraepithelial neoplasia through regulation of apoptotic and HIF-1-dependent pathways.
No sample metadata fields
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