# Parp3 assists muscle function and skeletal muscle differentiation by selectively adjusting H3K27me3 enrichment

## TL;DR

This study shows that Parp3 helps muscle development and function by controlling a specific histone modification that affects gene expression.

## Contribution

The study identifies Parp3 as a novel regulator of skeletal muscle differentiation and function through epigenetic mechanisms.

## Key findings

- Parp3 promotes skeletal muscle integrity and myogenic differentiation.
- Parp3 increases H3K27me3 enrichment on specific genes and interacts with Ezh2.
- Parp3 ADP-ribosylates Ezh2 in vitro, linking it to epigenetic control of gene expression.

## Abstract

Poly(ADP-ribose) polymerase 3 (Parp3) is known for its role in DNA repair, mitotic division, and cancer aggressiveness. Still, its physiological roles have yet to be defined. Here, we combined in vivo studies using Parp3-deficient mice with in cellulo studies to explore the involvement of Parp3 in skeletal muscle function and muscle differentiation. We show that Parp3 contributes to skeletal muscle integrity and promotes myogenic differentiation. Mechanistically, we show that Parp3 promotes the enrichment of the repressive histone mark H3K27me3 onto a panel of selected genes. For some genes, Parp3 also helps the binding of Ezh2, the histone methyltransferase that catalyzes H3K27me3. Moreover, Parp3 ADP-ribosylates Ezh2 in vitro. Altogether, these findings unveil Parp3 as a driver of efficient murine skeletal myogenesis in vitro and muscle function in young adults, and highlight an epigenetic control of gene expression.

•Parp3 drives efficient skeletal muscle differentiation in vitro•Parp3 contributes to skeletal muscle function and muscle integrity•Parp3 regulates the abundance of H3K27me3 onto a subset of selected genes

Parp3 drives efficient skeletal muscle differentiation in vitro

Parp3 contributes to skeletal muscle function and muscle integrity

Parp3 regulates the abundance of H3K27me3 onto a subset of selected genes

Molecular mechanism of gene regulation; Epigenetics; Molecular network; Cell biology; Model organism