Pluto Bioinformatics

GSE102774: Expression regulation by Pcgf3 and Pcgf5 in mouse embryonic stem cells

Bulk RNA sequencing

Polycomb group (PcG) proteins are epigenetic transcriptional repressors that orchestrate numerous developmental processes and have been implicated in the maintenance of embryonic stem (ES) cell state. More recently emerging evidence suggests a subset of PcG proteins engage in transcriptional activation in some cellular contexts. But how this property is exerted remains largely unknown. Here, we generated ES cells with single or combined disruption of Pcgf3 (Polycomb group RING finger protein 3) and Pcgf5 by CRISPR-Cas9 technology. We showed that although these mutant cells maintained their self-renewal and colony-formation capacity, they displayed severe defects in mesoderm differentiation in vitro. To gain a better understanding of the role of Pcgf3/5 in transcriptional control of differentiation, we analyzed transcriptional profiles of ES cells with single or combined Pcgf3/5 deficiency using RNA-seq. In contrast to the canonical role of PRC1 in gene repression, we found that Pcgf3/5 mainly functioned as a transcriptional activator to drive expression of many genes involved in mesoderm differentiation. Proteomic approaches and promoter occupancy analyses allowed us to establish an extended Pcgf3/5 interactome and identify several novel interactors including Tex10, which may directly contribute to transcription activation by cooperating with transcriptional co-activator p300. Furthermore, Pcgf3/5 deletion substantially reduces the occupancy of Tex10 and p300 at target genes. Finally, we demonstrated an essential role for Pcgf3/5 in regulating global H2AK119ub1 levels in ES cells. Collectively, our studies establish Pcgf3/5 as a transcriptional activator in ES cells by cooperating with Tex10 and p300, and point to a redundant mode of action for Pcgf3/5 in pluripotency maintenance. SOURCE: Wukui Zhao (zhaowukui163@163.com) - MOE Key Laboratory of Model Animal for Disease Study Nanjing University