Profiling ERRb-target genes in mouse ES cells

We found ERRb activates the transcription through two molecular pathways, which are interaction to AF2-region binding PGC-1a/cofactors and general transcription factor TFIIH. To analyze the significance of these pathways in cells, we first identified ERRb-target genes in ES cells. Estrogen-related receptors (ERRa/b/g) are orphan nuclear receptors that function in a number of energy-demanding physiological processes, as well as in development and stem cell maintenance, but mechanisms underlying target gene activation are largely unknown. Here, reconstituted biochemical assays that manifest ERR-dependent transcription have revealed two complementary mechanisms. On chromatin templates ERR-dependent transcription is dependent on interactions with cell-specific coactivator PGC-1a, which in turn recruits the ubiquitous p300 and MED1/Mediator coactivators. The N-terminal half of PGC-1a is necessary and sufficient for these interactions and for transcription both in vitro and in vivo. On DNA templates, ERRs activate transcription with just the normal complement of general initiation factors in a manner dependent upon interaction of the ERR DNA-binding domain with the p52 subunit of initiation factor TFIIH. Importantly, the PGC-1a and TFIIH interactions are both essential for ERRb/g functions in maintaining embryonic stem cell pluripotency through regulation of target gene transcription. ERRb gene in mouse ES cell line K3 was knockout. Then, was transduced with lentivirus expressing ERRb (KO/ERRb-wt)