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RMI1 and TOP3α limit meiotic CO formation through their C-terminal domains
Mathilde Séguéla-Arnaud1, Sandrine Choinard1, Cécile Larchevêque1
1Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78000 Versailles, France.
Nucleic Acids Research
|December 15, 2016
Summary
The RMI1 protein is crucial in meiosis for preventing excess crossovers and chromosome damage. Specific domains within RMI1 and TOP3α limit crossovers without affecting DNA repair resolution.
Area of Science:
- Genetics
- Molecular Biology
- Cell Biology
Background:
- Meiosis involves programmed DNA double-strand breaks (DSBs) repaired by homologous recombination.
- A subset of DSBs results in crossovers (COs), with at least one CO per chromosome pair required.
- The BLM-TOP3α-RMI1 (BTR) complex regulates meiotic recombination to ensure chromosome integrity and limit COs.
Purpose of the Study:
- To investigate the specific roles of RMI1 and TOP3α in meiotic recombination and chromosome integrity.
- To elucidate the function of C-terminal domains of RMI1 and TOP3α in preventing extra crossovers.
Main Methods:
- Characterization of specific mutants in Arabidopsis.
- Analysis of meiotic recombination intermediates and crossover outcomes.
- Investigation of chromosome entanglement and breakage.
Main Results:
- RMI1 acts as a major anti-crossover factor and is essential for preventing chromosome breakage and entanglement.
- Specific C-terminal domains of RMI1 (Oligo Binding domain) and TOP3α (Zinc finger motifs) are implicated in preventing extra crossovers.
- The BTR complex, specifically certain domains of RMI1 and TOP3α, can limit extra crossovers independently of resolving recombination intermediates.
Conclusions:
- RMI1 plays a critical role in limiting meiotic crossovers and maintaining chromosome stability.
- Distinct functional domains within the BTR complex contribute to the regulation of crossover number during meiosis.
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