BioProject

It is unclear how gene networks that regulate self-renewal and pluripotency of embryonic stem (ES) cells are established. More...

It is unclear how gene networks that regulate self-renewal and pluripotency of embryonic stem (ES) cells are established. We searched for factors that contribute to forming functional chromatin architecture in ES cells and identified Tip5 (also called Baz2a) as a genome organizer, folding chromatin and recruiting chromatin remodeling/epigenetic factors to genes. Tip5 binds specialized genomic sequences called base-unpairing regions (BURs) and localizes near heterochromatin. Through chromatin looping Tip5 recruits the polycomb-repressive complex 2 (PRC2) subunits and Jarid2 to target genes far from Tip5-bound BURs and alters their histone profiles. In ES cells Tip5 represses PRC2-bound developmental genes and regulates non-PRC2-bound genes that are enriched for G-protein coupled receptor signaling. Tip5 knockdown caused misexpression of these genes important for ES cell maintenance, leading to rapid ES cell differentiation and impaired pluripotency. These data suggest that Tip5 regulates multiple processes through ES cell-specific genome organization to maintain ES cell stemness. Overall design: Genome occupancy profiles of Tip5, Jarid2, Suz12, and relevant histone modifications, were determined for E14 and E14 Tip5-knockdown ES cells. Less...