The cohesin stabilizer Sororin drives G<sub>2</sub>-M transition and spindle assembly in mammalian oocytes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34559563.
- Also identified by DOI 10.1126/sciadv.abg9335 and PMC identifier 8462903.
- Licence recorded as CC BY-NC.
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Abstract
During the S phase of mitosis, Sororin is recruited by acetylated Smc3 and stabilizes sister chromatid cohesion by counteracting the Wapl-Pds5 interaction. Thereafter, Sororin is phosphorylated during prophase and translocated to the cytoplasm, where its function remains poorly understood. Here, we report that Sororin acts as a regulator of meiotic G<sub>2</sub>-M transition and spindle assembly in mammalian oocytes. Sororin is present in the nucleus of GV oocytes and becomes associated with the spindle apparatus during meiosis I in mice. Depletion of Sororin causes failure of GVBD due to inactivation of Cdk1 and defective spindle assembly because of reduced levels of Cyclin B2. We validate Sororin interactions with Cyclin B2 that protects it from destruction by APC<sup>Cdh1</sup>, which drives M phase entry and bipolar spindle formation. Notably, the meiotic functions of Sororin are conserved among mammals. Together, our findings provide novel insights into the noncanonical role of Sororin in the resumption of meiosis and progression through meiosis I in mammalian oocytes.