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Loss of Polycomb Group Protein Pcgf1 Severely Compromises Proper Differentiation of Embryonic Stem Cells
Yun Yan1, Wukui Zhao1, Yikai Huang1
1MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China.
Insights
Polycomb Repressive Complex 1 (PRC1) variant Pcgf1 is crucial for embryonic stem cell differentiation. Loss of Pcgf1 impairs differentiation by decreasing gene activation and H2AK119ub1 marks, revealing a novel role in lineage specification.
Area of Science:
- Developmental Biology
- Epigenetics
- Stem Cell Biology
Background:
- Polycomb Repressive Complex 1 (PRC1) regulates gene expression and cell fate.
- Six major PRC1 variants exist, defined by Pcgf subunits, but their specific roles are unclear.
- Understanding PRC1 variant function is key to deciphering cell fate decisions.
Purpose of the Study:
- Investigate the role of Pcgf1, a PRC1 subunit, in mouse embryonic stem cell (ES cell) differentiation.
- Elucidate the mechanism by which Pcgf1 influences transcriptional control during lineage specification.
Main Methods:
- CRISPR/Cas9 gene editing to disrupt Pcgf1 in mouse ES cells.
- RNA sequencing (RNA-seq) to analyze gene expression profiles.
- Chromatin immunoprecipitation (ChIP) to assess protein and mark binding.
Main Results:
- Pcgf1-deficient ES cells showed normal self-renewal but severe differentiation defects.
- RNA-seq revealed Pcgf1 positively regulates key transcription factors for ectoderm and mesoderm differentiation.
- Pcgf1 deletion reduced binding of Ring1B and H2AK119ub1 to target genes.
Conclusions:
- Pcgf1 plays an unexpected role in gene activation during ES cell lineage specification.
- Pcgf1 is essential for promoting differentiation by facilitating target gene expression and H2AK119ub1 deposition.
- This study uncovers a novel function of a PRC1 variant in maintaining cell fate plasticity.
Abstract:
The Polycomb repressive complex 1 (PRC1) is essential for fate decisions of embryonic stem (ES) cells. Emerging evidence suggests that six major variants of PRC1 complex, defined by the mutually exclusive presence of Pcgf subunit, regulate distinct biological processes, yet very little is known about the mechanism by which each version of PRC1 instructs and maintains cell fate. Here, we disrupted the Pcgf1, also known as Nspc1 and one of six Pcgf paralogs, in mouse ES cells by the CRISPR/Cas9 technology. We showed that although these mutant cells were viable and retained normal self-renewal, they displayed severe defects in differentiation in vitro. To gain a better understanding of the role of Pcgf1 in transcriptional control of differentiation, we analysed mRNA profiles from Pcgf1 deficient cells using RNA-seq. Interestingly, we found that Pcgf1 positively regulated expression of essential transcription factors involved in ectoderm and mesoderm differentiation, revealing an unexpected function of Pcgf1 in gene activation during ES cell lineage specification. Chromatin immunoprecipitation experiments demonstrated that Pcgf1 deletion caused a decrease in Ring1B and its associated H2AK119ub1 mark binding to target genes. Altogether, our results suggested an unexpected function of Pcgf1 in gene activation during ES cell maintenance.