Roles of Budding Yeast Hrr25 in Recombination and Sporulation.

Hrr25, a casein kinase 1 δ/ε homolog in budding yeast, is essential to set up mono-orientation of sister kinetochores during meiosis. Hrr25 kinase activity coordinates sister chromatid cohesion via cohesin phosphorylation. Here, we investigated the prophase role of Hrr25 using the auxin-inducible degron system and by ectopic expression of Hrr25 during yeast meiosis. Hrr25 mediates nuclear division in meiosis I but does not affect DNA replication. We also found that initiation of meiotic double-strand breaks as well as joint molecule formation were normal in HRR25-deficient cells. Thus, Hrr25 is essential for termination of meiotic division but not homologous recombination.