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Updated: Mar 17, 2026

Preparation of Meiotic Chromosome Spreads from Mouse Oocytes for Assessment of Synapsis and Recombination
Published on: July 18, 2025
H2B ubiquitination regulates meiotic recombination by promoting chromatin relaxation
Zhiliang Xu1,2, Zhenhua Song1,2, Guoping Li3
1State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Abstract:
Meiotic recombination is essential for fertility in most sexually reproducing species, but the molecular mechanisms underlying this process remain poorly understood in mammals. Here, we show that RNF20-mediated H2B ubiquitination is required for meiotic recombination. A germ cell-specific knockout of the H2B ubiquitination E3 ligase RNF20 results in complete male infertility. The Stra8-Rnf20-/- spermatocytes arrest at the pachytene stage because of impaired programmed double-strand break (DSB) repair. Further investigations reveal that the depletion of RNF20 in the germ cells affects chromatin relaxation, thus preventing programmed DSB repair factors from being recruited to proper positions on the chromatin. The gametogenetic defects of the H2B ubiquitination deficient cells could be partially rescued by forced chromatin relaxation. Taken together, our results demonstrate that RNF20/Bre1p-mediated H2B ubiquitination regulates meiotic recombination by promoting chromatin relaxation, and suggest an old drug may provide a new way to treat some oligo- or azoospermia patients with chromatin relaxation disorders.
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