July 8th, 2024 (1/2)

Today is a special day for the lab. The current issue of Nucleic Acids Research features two papers from the group reflecting the PhD projects of Raquel Carreira Rodríguez and Tomás Lama Díaz.

Raquel´s paper, Concurrent D-loop cleavage by Mus81 and Yen1 yields half-crossover precursors, culminates a long collaboration with the Lumir Krejci´s lab at Masaryk University (Brno, Czech Republic) where she spearheaded the characterization of the activitites of the yeast structure-selective nucleases Mus81-Mms4 and Yen1 on various D-loop substrates.

Our biochemical approach demonstrated that both enzymes can cleave this central recombination intermediate. Crucially, we show for the first time that the simultaneous action of Mus81 and Yen1 on a D-loop, followed by ligation, is sufficient to recreate the formation of a half-crossover precursor in vitro. Our results provide a mechanistic explanation for the formation of half-crossovers and chromosomal loss events that is consistent with previous genetic data, highlighting the relevance of the tight regulation of these SSEs to prevent chromosomal rearrangements.