AHI-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.
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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.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
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 Samplesthere is presently no methodology that adequately isolates pure MaSCs. Seeking new markers of MaSCs, we characterized the stem-like properties and expression signature of label-retaining cells from the mammary gland of mice expressing a controllable H2b-GFP transgene. According to their transcriptome profile, H2b-GFPh MaSCs are enriched for pathways thought to play important roles in adult stem cells.
Molecular hierarchy of mammary differentiation yields refined markers of mammary stem cells.
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View SamplesThe ubiquitously expressed RNA-binding protein Hu Antigen R (HuR) or ELAVL1 is implicated in a variety of biological processes as well as being linked with a number of diseases, including cancer. Despite a great deal of prior investigation into HuR, there is still much to learn about its function. We take an important step in this direction by conducting iCLIP (CrossLinking and ImmunoPreciptation) and RNA Sequencing experiments followed by an extensive computational analysis to determine the characteristics of the HuR binding site and impact on the transcriptome. We reveal that HuR targets predominantly uracil-rich single-stranded stretches of varying size, with a strong conservation of structure and sequence composition. Despite the fact that HuR sites are observed in intronic regions, our data does not support a role for HuR in regulating splicing. HuR sites in 3'UTRs overlap extensively with predicted miRNA target sites suggesting interplay between the functions of HuR and miRNAs. Network analysis showed that identified targets containing HuR binding sites in the 3' UTR are highly interconnected.
Genomic analyses of the RNA-binding protein Hu antigen R (HuR) identify a complex network of target genes and novel characteristics of its binding sites.
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View SamplesExpression data from four different lifespan-extending conditions: dietary restriction in two different genetic backgrounds (canton-s and a yw, w1118 combination), sir2 overexpression and p53 knockdown (+/-).
Comparative transcriptional profiling identifies takeout as a gene that regulates life span.
Sex, Age, Specimen part
View SamplesFeeding resveratrol to Drosophila melanogaster extends lifespan. Studies of microarray show similarities between calorie/dietary restriction and resveratrol on both a gene expression and biological pathway level.
Comparative transcriptional pathway bioinformatic analysis of dietary restriction, Sir2, p53 and resveratrol life span extension in Drosophila.
Sex, Age, Specimen part
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 SamplesR1 ESC were cultured for 18h and 72h without leukemia inhibitory factor
Correlation of murine embryonic stem cell gene expression profiles with functional measures of pluripotency
Specimen part, Cell line, Time
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