Wnt3a-Activin A Synergy Induces eRNAPII Pause-Release and Counteracts a Yap1 Elongation Block during hESC Differentiation
Ontology highlight
ABSTRACT: The Wnt3a/β-catenin and Activin/Smad2,3 signaling pathways synergize to induce endodermal differentiation of human embryonic stem cells, however the mechanism is not well-understood. Using ChIP-seq and GRO-seq analyses, we report here that hESC enhancers, including Wnt3a/LEF-1 sites, hold enhancer RNAPII complexes (eRNAPII) containing high levels of Ser5P and low Ser7P. In Wnt3a signaling, β-catenin recruits cohesin to the LEF-1:eRNAPII sites to induce enhancer-promoter looping and activate transcription of mesoendodermal (ME) genes. However, paused Ser5P-RNAPII complexes accumulate at these genes, indicating that elongation remains limiting. Subsequent Activin/Smad2,3 signaling increases P-TEFb occupancy, CTD-Ser7P, and productive elongation at ME genes. Additionally, ME genes, including EOMES and MIXL1, are repressed by the Hippo regulator, Yap1, an essential pluripotency factor. GRO-seq experiments indicate that Yap1 blocks nascent transcription and controls NELF occupancy on ME genes. Thus, Wnt3a/β-catenin and Activin/Smad2,3 pathways up-regulate transcription initiation and elongation, respectively, to overcome Yap1 repression during early hESC differentiation
ORGANISM(S): Homo sapiens
PROVIDER: GSE64758 | GEO | 2015/05/04
SECONDARY ACCESSION(S): PRJNA271823
REPOSITORIES: GEO
ACCESS DATA