Loss of Notch1 in retinal progenitor cells (RPCs) during postnatal retinal development results in the overproduction of rod photoreceptors at the expense of interneurons and glia. To examine the molecular underpinnings of this observation, microarray analysis of singla retinal cells from wildtype (WT) or Notch1 conditional knockout (N1-CKO) retinas was performed. The majority of N1-CKO cells lost expression of known Notch target genes. These cells also had low levels of RPC and cell cycle genes, and robustly upregulated rod precursor genes. In addition, single WT cells, in which cell cycle marker genes were downregulated, expressed markers of both rod photoreceptors and interneurons. These results demonstrate that individual, newly postmitotic retinal cells can begin to differentiate into more than one cell type, and that this transitional state may be dependent on Notch1 signaling.
Notch1 is required in newly postmitotic cells to inhibit the rod photoreceptor fate.
Specimen part
View SamplesWe examined the transcriptional function of cyclin D1 in mouse development using two approaches. First, we queried association of cyclin D1 with the genome of E14.5 mouse embryos using ChIP-on-chip approach. We observed binding of cyclin D1 to several promoter regions. Second, we compared gene expression profiles between wild-type and cyclin D1-null retinas. We observed several transcripts with altered levels in cyclin D1-null organs.
Transcriptional role of cyclin D1 in development revealed by a genetic-proteomic screen.
No sample metadata fields
View SamplesThe association between chronic inflammation and the development and progression of malignancy is exemplified in the biliary tract where persistent inflammation strongly predisposes to cholangiocarcinoma. The inflammatory cytokine interleukin-6 (IL-6) enhances tumor growth in cholangiocarcinoma by altered gene expression via autocrine mechanisms. We therefore investigated the effect of chronic exposure to IL-6 on gene expression using malignant cholangiocytes stably transfected to overexpress IL-6. Comparison of gene expression identified several genes that were altered by enforced IL-6 expression.
Interleukin-6 contributes to growth in cholangiocarcinoma cells by aberrant promoter methylation and gene expression.
No sample metadata fields
View SamplesWe generated whole genome expression profiles from a homogeneous population of purified pacemaker neurons (ventral Lateral Neurons, LNvs) from wild type and clock mutant Drosophila. The study identifes a group of genes whose expression is highly enriched in LNvs compared to other neurons; and a second group of genes rhythmically expressed in LNvs in a clock-dependent manner.
A mechanism for circadian control of pacemaker neuron excitability.
Specimen part
View SamplesTo identify early processes in carcinogenesis, we used an in vitro model, based on the initiating event in cervical cancer, human papillomavirus (HPV) transformation of keratinocytes. We compared gene expression in primary keratinocytes (K) and HPV16-transformed keratinocytes from early (E) and late (L) passages, and from benzo[a]pyrene treated L cells (BP). The transformed cells exhibit similar transcriptional changes to clinical cervical carcinoma. We revealed a contraction in expression of the apoptotic network during HF1 cell transformation, which affected the ability of L and BP cells to execute apoptosis, but did not lead to resistance to apoptotic stimuli. The contraction in the apoptotic machinery during the process of transformation was accompanied by a switch from apoptosis to necrosis in response to CDDP. The shrinkage of the pro- and anti-apoptotic networks appears to be part of a general contraction in the number of genes transcribed in L and BP cells. We also identified a large group of genes with induced expression, which are involved in cell metabolism and cell cycle, suggesting increased investment of the transformed cell in cellular proliferation. We hypothesize that the decrease in expression of many diverse pathways, including the pro- and anti-apoptotic networks, cuts the energy requirements for cell maintenance, allowing energy to be diverted towards rapid cell proliferation. This study supports the hypothesis that the process of cancer transformation may be accompanied by a shift from apoptosis to necrosis.
Shift from apoptotic to necrotic cell death during human papillomavirus-induced transformation of keratinocytes.
Specimen part, Cell line
View SamplesTumor-specific alternative splicing is implicated in the progression of cancer, including clear cell renal cell carcinoma (ccRCC). Using ccRCC RNA-sequencing data from The Cancer Genome Atlas, we found that epithelial splicing regulatory protein 2 (ESRP2), one of the key regulators of alternative splicing in epithelial cells, is expressed in ccRCC. ESRP2 mRNA expression did not correlate with the overall survival rate of ccRCC patients, but the expression of some ESRP-target exons correlated with the good prognosis and with the expression of Arkadia (also known as RNF111) in ccRCC. Arkadia physically interacted with ESRP2, induced polyubiquitination, and modulated its splicing function. Arkadia and ESRP2 suppressed ccRCC tumor growth in a coordinated manner. Lower expression of Arkadia correlated with advanced tumor stages and poor outcomes in ccRCC patients. This study thus reveals a novel tumor-suppressive role of the Arkadia-ESRP2 axis in ccRCC. Overall design: Expression of mRNA in a ccRCC cell line OS-RC-2 under the knockdown of Arkadia or ESRP2. Knock-down of ESRP2 was confirmed by RT-PCR because of low expression of ESRP2 which resulted in non-quantitative FPKM value.
The Arkadia-ESRP2 axis suppresses tumor progression: analyses in clear-cell renal cell carcinoma.
No sample metadata fields
View SamplesWe evaluated the role of Arkadia and ESRP2 in HEK293T cells Overall design: Expression of mRNA in HEK293T cells under the knockdown of Arkadia or ESRP2
The Arkadia-ESRP2 axis suppresses tumor progression: analyses in clear-cell renal cell carcinoma.
No sample metadata fields
View SamplesAnalysis of synchronized HCT116 cells at various time points up to 10 hours following treatment with DMSO or Nocodazole.
A signature-based method for indexing cell cycle phase distribution from microarray profiles.
Cell line, Treatment
View SamplesThe aim of this study is to investigate the gene expression profiles during masculinization of neonatal female mice brain by exogenous androgen treatment.
Gene expression profile of the neonatal female mouse brain after administration of testosterone propionate.
Sex, Specimen part, Treatment
View SamplesWe used microarrays to reveal the global expression profiles of young and old whole lateral ventricle choroid plexus tissue.
Age-Dependent Niche Signals from the Choroid Plexus Regulate Adult Neural Stem Cells.
Sex, Specimen part
View Samples