RNA is essential for PRC2 chromatin occupancy and function in human pluripotent stem cells

Area of Science:

• Epigenetics and Gene Regulation
• Stem Cell Biology
• Molecular Biology

Background:

• Many proteins that regulate DNA also interact with RNA.
• Polycomb repressive complex 2 (PRC2) is crucial for gene silencing and stem cell differentiation, depositing the H3K27me3 mark.
• PRC2's interaction with RNA has been observed but its functional significance is unclear.

Purpose of the Study:

• To investigate the biological importance of RNA binding by PRC2 in human induced pluripotent stem cells.
• To determine if RNA interaction is necessary for PRC2's function in chromatin localization and cellular differentiation.

Main Methods:

• Utilized RNase A treatment to disrupt RNA-PRC2 interactions.
• Employed a chemical transcription inhibitor to perturb RNA binding.
• Used an RNA-binding-defective PRC2 mutant.
• Assessed PRC2 chromatin occupancy and genome-wide localization.
• Examined cardiomyocyte differentiation following genetic disruption of PRC2-RNA interaction.

Main Results:

• Disrupting RNA-PRC2 interactions using RNase A, a transcription inhibitor, or a mutant PRC2 impaired PRC2's chromatin occupancy and genome-wide localization.
• Genetic disruption of PRC2-RNA interactions led to defects in cardiomyocyte differentiation.
• PRC2 binding to RNA is essential for its proper localization to chromatin.

Conclusions:

• RNA binding is a critical requirement for Polycomb repressive complex 2 (PRC2) chromatin localization in human pluripotent stem cells.
• This RNA-dependent chromatin localization is fundamental for PRC2's role in defining cellular states and enabling differentiation.