Oct4, Sox2, Klf4, and cMyc (OSKM) reprogram somatic cells to pluripotency. To gain a mechanistic understanding of their function, we mapped OSKM-binding, stage-specific transcription-factors (TFs), and chromatin-states in discrete reprogramming stages and performed loss- and gain-of-function experiments. We found that early in reprogramming OSK extensively bind somatic-enhancers and initiate their decommissioning by recruiting Hdac1. Concurrently, OSK engage other sites, including specific pluripotency-enhancers, and induce the relocation of somatic TFs to these sites and away from somatic-enhancers, extending somatic-enhancer decommissioning genome-wide. Pluripotency-enhancer selection early in reprogramming occurs predominantly at sites with high OSK-motif densities and requires collaborative binding by OSK. Most pluripotency-enhancers are selected later and occupied by OS and stage-specific-TFs like Esrrb. Overexpression of stage-specific-TFs influences reprogramming efficiency by changing OSK-occupancy, somatic-enhancer decommissioning, and pluripotency-enhancer selection. We propose that collaborative interactions among OSK and with stage-specific-TFs direct both somatic-enhancer decommissioning and pluripotency-enhancer selection, which drives the enhancer reorganization underlying reprogramming Overall design: RNA-seq
Cooperative Binding of Transcription Factors Orchestrates Reprogramming.
Specimen part, Cell line, Subject
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Dual Roles of RNF2 in Melanoma Progression.
Specimen part, Cell line
View SamplesEpigenetic regulators have emerged as critical factors governing the biology of cancer. Here, in the context of melanoma, we show that RNF2 is prognostic, exhibiting progression-correlated expression in human melanocytic neoplasms.
Dual Roles of RNF2 in Melanoma Progression.
Specimen part, Cell line
View SamplesPrion diseases are fatal neurodegenerative disorders that include bovine spongiform encephalopathy (BSE) and scrapie in animals and Creutzfeldt-Jakob disease (CJD) in humans. They are characterized by long incubation periods, variation in which is determined by many factors including genetic background. In some cases it is possible that incubation time may be directly correlated to the level of gene expression. In order to test this hypothesis we combined incubation time data from five different inbred lines of mice with quantitative gene expression profiling in normal brains and identified five genes with expression levels that correlate with incubation time. One of these genes, Hspa13 (Stch), is a member of the Hsp70 family of ATPase heat shock proteins which have been previously implicated in prion propagation. To test whether Hspa13 plays a causal role in determining the incubation period we tested two over-expressing mouse models. The Tc1 human chromosome 21 (Hsa21) transchromosomic mouse model of Down syndrome is trisomic for many Hsa21 genes including Hspa13 and following Chandler/RML prion inoculation shows a 4% reduction in incubation time. Furthermore, a transgenic model with eight fold over-expression of mouse Hspa13 exhibited highly significant reductions in incubation time of 16%, 15% and 7% following infection with Chandler/RML, ME7 and MRC2 prion strains respectively. These data further implicate Hsp70-like molecular chaperones in protein misfolding disorders such as prion disease.
Overexpression of the Hspa13 (Stch) gene reduces prion disease incubation time in mice.
Specimen part
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