SCFRMF mediates degradation of the meiosis-specific recombinase DMC1

In eukaryotes the recombinase DMC1 is required for meiotic recombination, but it remains unclear how DMC1 stability is regulated. Here the authors identify a SCF complex which mediates ubiquitination and proteasomal degradation of DMC1. Meiotic recombination requires the specific RecA homolog DMC1 recombinase to stabilize strand exchange intermediates in most eukaryotes. Normal DMC1 levels are crucial for its function, yet the regulatory mechanisms of DMC1 stability are unknown in any organism. Here, we show that the degradation of Arabidopsis DMC1 by the 26S proteasome depends on F-box proteins RMF1/2-mediated ubiquitination. Furthermore, RMF1/2 interact with the Skp1 ortholog ASK1 to form the ubiquitin ligase complex SCFRMF1/2. Genetic analyses demonstrate that RMF1/2, ASK1 and DMC1 act in the same pathway downstream of SPO11-1 dependent meiotic DNA double strand break formation and that the proper removal of DMC1 is crucial for meiotic crossover formation. Moreover, six DMC1 lysine residues were identified as important for its ubiquitination but not its interaction with RMF1/2. Our results reveal mechanistic insights into how the stability of a key meiotic recombinase that is broadly conserved in eukaryotes is regulated.

Automated summary

In this study, a SCF complex is found to regulate the stability of DMC1 through ubiquitination and proteasomal degradation. The interaction between RMF1/2, ASK1 and DMC1 in the same pathway is demonstrated, and the proper removal of DMC1 is crucial for meiotic crossover formation.