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COSA-1 mediated pro-crossover complex formation promotes meiotic crossing over in C. elegans
Yuejun Yang1, Nan Wang1, Guoteng Liu1
1Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China.
Nucleic Acids Research
|February 27, 2024
Summary
COSA-1 protein interactions are crucial for assembling recombination complexes that ensure accurate chromosome segregation during meiosis. These complexes protect key recombination intermediates, promoting successful crossover formation.
Area of Science:
- Genetics
- Cell Biology
- Molecular Biology
Background:
- Accurate chromosome segregation during meiosis is essential for sexual reproduction.
- Meiotic crossover (CO) formation requires conserved pro-CO proteins that localize to specific sites.
- The precise function and complex formation of these pro-CO proteins in vivo remain incompletely understood.
Purpose of the Study:
- To investigate the role of COSA-1 in pro-CO complex assembly and its contribution to meiotic CO formation.
- To determine how COSA-1 interacts with other pro-CO factors like MSH-5 and ZHP-3.
- To elucidate the mechanism by which COSA-1 promotes the formation of functional recombination nodules.
Main Methods:
- Co-immunoprecipitation assays to study protein interactions.
- Site-directed mutagenesis to disrupt specific protein-protein interactions.
- Microscopy to visualize protein localization and foci formation.
- Genetic analysis to assess the effects of mutations on CO formation and recombination intermediates.
Main Results:
- COSA-1 interacts with MSH-5 and ZHP-3 through its N-terminal disordered region.
- Mutations impairing COSA-1 interactions hinder its accumulation at designated sites and disrupt CO formation.
- Artificial tethering of mutated COSA-1 to ZHP-3 can partially rescue CO formation defects.
- COSA-1 foci are necessary for assembling functional recombination nodules that protect recombination intermediates.
Conclusions:
- COSA-1 acts as a scaffold, mediating the assembly of a functional pro-CO complex.
- This complex is critical for protecting meiotic recombination intermediates from premature dismantling and ensuring proper resolution.
- The findings clarify COSA-1's mechanism in promoting meiotic crossovers and maintaining genomic stability.
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