Crossovers are regulated by a conserved and disordered synaptonemal complex domain

Area of Science:

• Genetics
• Molecular Biology
• Cell Biology

Background:

• Meiosis requires precise regulation of crossover (CO) number and distribution for genomic stability.
• The synaptonemal complex (SC) is essential for proper chromosome pairing and segregation during meiosis.
• CO assurance and interference are critical mechanisms preventing aneuploidy.

Purpose of the Study:

• To investigate the role of the synaptonemal complex (SC) in regulating meiotic crossovers (COs).
• To identify the specific protein domain and molecular mechanisms involved in CO regulation.
• To understand how SC structure contributes to CO assurance and interference.

Main Methods:

• Analysis of SYP-4 C-terminal domain mutations in Caenorhabditis elegans.
• Investigating the role of phosphorylation and conserved phenylalanines in CO regulation.
• Assessing the impact of these mutations on synapsis, CO assurance, and interference.

Main Results:

• A disordered C-terminal domain of SYP-4 is essential for CO assurance and interference, but not synapsis.
• Phosphorylation is not the primary regulator; nine conserved phenylalanines are critical.
• These phenylalanines recruit a pro-CO factor, likely an E3 ligase, and influence SC physical properties.

Conclusions:

• The conserved, disordered C-terminal domain of SYP-4 plays a vital role in regulating meiotic COs.
• This domain maintains the SC in a state conducive to signaling for CO formation.
• Proper CO regulation by the SC is crucial for safeguarding the genome.