Elucidation of novel budding yeast separase mutants

Abstract

<p>The mitotic separase cleaves Scc1 in cohesin to allow sister chromatids to separate from each other upon anaphase onset. Separase is also required for DNA damage repair. Here, we isolated and characterized 10 temperature-sensitive (ts) mutants of separase <i>ESP1</i> in the budding yeast <i>Saccharomyces cerevisiae</i>. All mutants were defective in sister chromatid separation at the restricted temperature. Some <i>esp1</i>-<i>ts</i> mutants were hypersensitive to the microtubule poison benomyl and/or the DNA-damaging agent bleomycin. Overexpression of securin alleviated the growth defect in some <i>esp1</i>-<i>ts</i> mutants, whereas it rather exacerbated it in others. The <i>Drosophila</i> Pumilio homolog <i>MPT5</i> was isolated as a high-dosage suppressor of <i>esp1</i>-<i>ts</i> cells. We discuss various features of separase based on these findings.</p> <p>Securin positively and negatively regulates separase function. In addition, extracellular inputs affect separase function.</p