H4K44 Acetylation Facilitates Chromatin Accessibility during Meiosis.

Area of Science:

• Genetics
• Epigenetics
• Molecular Biology

Background:

• Meiotic recombination hotspots correlate with histone modifications and open chromatin.
• The precise regulatory mechanisms linking histone modifications and chromatin structure to meiotic recombination remain largely unknown.

Purpose of the Study:

• To investigate the role of histone H4 acetylation at Lys44 (H4K44ac) in regulating meiotic recombination.
• To determine how H4K44ac influences chromatin structure and double-strand break (DSB) formation during meiosis.

Main Methods:

• Identification and characterization of H4K44ac.
• Analysis of H4K44ac enrichment at recombination hotspots.
• Assessment of meiotic recombination, DSB levels, and sporulation in wild-type and H4K44R mutant strains.
• ChIP-seq to analyze nucleosomal occupancy.

Main Results:

• H4K44ac occurs on the nucleosomal lateral surface and is enriched at meiotic recombination hotspots.
• H4K44ac is essential for normal meiotic recombination, DSB formation, and sporulation.
• A non-modifiable H4K44R mutation leads to increased nucleosomal occupancy at DSB hotspots.

Conclusions:

• H4K44ac facilitates chromatin accessibility at recombination hotspots.
• This epigenetic modification is critical for promoting DSB formation and ensuring accurate meiotic recombination.