Synaptonemal complex (SC) assembly between paired homologous chromosomes plays a vital role in ensuring correct homologous recombination during meiosis. However, the mechanisms underlying the genetic regulation of SC assembly remain unclear.

In a study published in Cell Reports (DOI:10.1016/j.celrep.2021.109941), a research group led by Professor Cheng Zhukuan from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, using a map-based cloning strategy, identified a novel RING finger E3 ubiquitin ligase encoding gene, DESYNAPSIS1 (DSNP1), participating in synapsis and homologous recombination.

Super-resolution structured illumination microscopy analysis of SC assembly [IMAGE: IGDB]

An E3 ubiquitin ligase DSNP1 plays an essential role during rice meiosis. [IMAGE: IGDB]

In the dsnp1 mutant, aberrant SC-like polycomplexes with ZEP1 as a skeleton, such as in wild-type late leptotene meiocytes, formed independently of homologous chromosomes at prophase I. And MG132 treated wild-type meiocytes showed aggregation of ZEP1 proteins similar to those observed in dsnp1, suggesting a significant role of the DSNP1-mediated proteasome pathway in degrading aberrant SC-like polycomplexes.

Moreover, recombination factors including HEI10, MER3, and ZIP43 were trapped in ZEP1 polycomplexes, leading to a decreased foci of these recombination factors on meiotic chromosomes and a dramatic reduction in the number of crossovers (COs) in dsnp1.

Interestingly, the introduction of ZEP1 mutation in a dsnp1 background could to a great extent restore the localization of ZMM proteins on meiotic chromosomes and the formation of COs.

These findings indicate that the stabilization of canonical tripartite SC structures along paired homologous chromosomes and further formation of COs are regulated by the component of the Ubiquitin-proteasome pathway, DSNP1. This study provides new insights into the mechanisms of the meiotic process.

For more information, please contact:

Dr. Cheng Zhukuan

E-mail: zkcheng@genetics.ac.cn

Institute of Genetics and Developmental Biology (IGDB),

Chinese Academy of Sciences

Source: Institute of Genetics and Developmental Biology (IGDB),

Chinese Academy of Sciences