AbstractMeiotic defects derived from incorrect DNA repair during gametogenesis can lead to mutations, aneuploidies and infertility. Effective and coordinated resolution of meiotic recombination intermediates is necessary to accomplish both rounds of successful chromosome segregation. Cdc14 is an evolutionarily conserved dual-specificity phosphatase required for mitotic exit and meiotic progression. Mutations that inactivate the phosphatase lead to meiotic failure. Here, we have identified previously undescribed roles of Cdc14 in ensuring correct meiotic recombination. We found that recombination intermediates accumulate during prophase I when Cdc14 is depleted. Furthermore, Cdc14 plays a role in correct homolog disjunction at the end of anaphase I, both by modulating the timely removal of arm-cohesion between sister chromatids and by promoting elimination of SPO11-dependent entanglements. We also demonstrate that Cdc14 is required for correct sister chromatid segregation during the second meiotic division, independent of centromeric cohesion but dependent on the correct reduplication of SPBs during meiosis II, and on the activity of the Holliday Junction resolvase Yen1/GEN1. Timely activation of Yen1/GEN1 in anaphase I and II is impaired in the meiosis defective allele, cdc143HA. Based on these new findings, we propose previously undescribed functions of Cdc14 in the regulation of meiotic recombination; roles that are independent of sister chromatid cohesion, spindle dynamics and the metabolism of gamete morphogenesis.Author SummaryMeiotic recombination is fundamental for sexual reproduction, with efficient and orchestrated resolution of recombination intermediates critical for correct chromosome segregation. Homologous recombination is initiated by the introduction of programmed DNA Double-Strand Breakds (DSBs) followed by the formation of complex branched DNA intermediates, including double Holliday Junctions (dHJs). These recombination intermediates are eventually repaired into crossover or non-crossover products. In some cases, unresolved recombination intermediates, or toxic repair products, might persist until the metaphase to anaphase transition, requiring a set of late-acting repair enzymes to process them. Unrestrained activity of these enzymes, however, is equally detrimental for genome integrity, thus several layers of regulation tightly control them. For example, in budding yeast meiosis, Yen1/GEN1 is mainly activated during the second meiotic division, although how it is activated is unknown. Here, we have identified that the phosphatase Cdc14 is required during meiotic divisions for timely nuclear localization and activation of Yen1 in budding yeast meiosis. Additionally, we have been able to identify previously undescribed roles of Cdc14 in controlling meiotic recombination. Strikingly, we found that levels of recombination intermediates increase during prophase I in cdc14 meiotic deficient cells, indicating that Cdc14 plays a direct role in monitoring meiotic DSB repair, possibly in Yen1-independent manner. Resolution of recombination intermediates in the absence of Cdc14 is dependent on SGS1 and MUS81/MMS4, otherwise accumulating different types of aberrant recombination intermediates and a highly reduced efficiency in CO formation. Deficient resolution of JMs in cdc14 meiotic cells, together with difficulties in SPB reduplication, likely contribute to the missegregation problems observed during the second meiotic division.
Immediate visualization of recombination events and chromosome segregation defects in fission yeast meiosis