PCGF1-PRC1 links chromatin repression with DNA replication during hematopoietic cell lineage commitment

Junichiro Takano1,2,3, Shinsuke Ito2, Yixing Dong2

  • 1Laboratory for Immune Regeneration, RIKEN Center for Integrative Medical Sciences (RIKEN-IMS), Yokohama, Kanagawa, Japan.

Nature Communications
|November 28, 2022
PubMed

Insights

Polycomb repressive complex 1 (PRC1) containing PCGF1 ensures proper DNA replication in hematopoietic stem cells. This maintains correct chromatin structure, gene silencing, and prevents premature myeloid differentiation for lifelong hematopoiesis.

Area of Science:

  • Developmental Biology
  • Epigenetics
  • Stem Cell Biology

Background:

  • Polycomb group proteins (PcG) are crucial for maintaining cellular identity by repressing inappropriate genes.
  • Polycomb repressive complex 1 (PRC1) is known to localize at replication forks, but its specific function during DNA replication remains unclear.
  • Hematopoietic stem and progenitor cells (HSPCs) require precise regulation to maintain their differentiation potential.

Purpose of the Study:

  • To elucidate the precise functions of PRC1 during DNA replication in HSPCs.
  • To investigate the role of a specific PRC1 variant, PCGF1-PRC1, in regulating chromatin configuration and gene expression.
  • To understand how PCGF1-PRC1 contributes to the maintenance of HSPC differentiation potential.

Main Methods:

  • Utilized molecular biology techniques to study the interaction of PCGF1-PRC1 with nascent DNA during replication.
  • Analyzed chromatin configurations and nucleosome deposition in HSPCs.
  • Investigated gene expression patterns, focusing on PRC2 target genes like Hmga2, and assessed myeloid differentiation markers.

Main Results:

  • Identified a variant PRC1 containing PCGF1 (PCGF1-PRC1) that regulates the deposition of nucleosomes and chromatin structure at the replication fork.
  • Demonstrated that PCGF1-PRC1 prevents the overloading of activators and chromatin remodelers on nascent DNA.
  • Showed that PCGF1-PRC1 facilitates PRC2-mediated repression of genes such as Hmga2, thereby restricting premature myeloid differentiation.

Conclusions:

  • PCGF1-PRC1 plays a critical role in maintaining the fidelity of DNA replication and chromatin organization in HSPCs.
  • This function links proper nucleosome configuration at the replication fork with Polycomb-mediated gene silencing.
  • PCGF1-PRC1 is essential for preserving the differentiation potential of HSPCs, ensuring life-long hematopoiesis.

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