H4K44 Acetylation Facilitates Chromatin Accessibility during Meiosis

• H4K44 is acetylated in sporulating cells but not in vegetative cells
• H4K44ac is required for normal meiotic recombination
• H4K44ac is associated with meiotic DSB hotspots genome-wide
• H4K44ac confers chromatin accessibility at DSB hotspots

SummaryMeiotic recombination hotspots are associated with histone post-translational modifications and open chromatin. However, it remains unclear how histone modifications and chromatin structure regulate meiotic recombination. Here, we identify acetylation of histone H4 at Lys44 (H4K44ac) occurring on the nucleosomal lateral surface. We show that H4K44 is acetylated at pre-meiosis and meiosis and displays genome-wide enrichment at recombination hotspots in meiosis. Acetylation at H4K44 is required for normal meiotic recombination, normal levels of double-strand breaks (DSBs) during meiosis, and optimal sporulation. Non-modifiable H4K44R results in increased nucleosomal occupancy around DSB hotspots. Our results indicate that H4K44ac functions to facilitate chromatin accessibility favorable for normal DSB formation and meiotic recombination.

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