Auto-sumoylation of UBC9 coordinates meiotic progression and preserves the ovarian reserve in mice

Researchers have posted a preprint to bioRxiv describing in vivo characterisation of auto-sumoylation of UBC9, the sole E2-conjugating enzyme in the SUMO pathway. Previous in vitro work established that auto-sumoylation of UBC9 at lysine 14 (K14) alters its substrate selectivity, but the physiological significance of this modification had not been tested in a living organism.

Using Ubc9K14R/K14R knock-in mice — in which K14 is mutated to arginine to prevent auto-sumoylation at this site — the team reports a range of defects during meiotic prophase I. These include altered assembly of DNA strand-exchange complexes and delayed or defective synapsis between homologous chromosomes. Knock-in females also showed reduced ovarian reserves compared with wild-type controls, suggesting the modification is important for the long-term pool of oocytes available for reproduction.

SUMO-mediated regulation of meiosis is an active area of research, with relevance to understanding causes of primary ovarian insufficiency and infertility at the molecular level. The study has not yet been peer-reviewed. It is primarily of interest to researchers in meiosis biology, reproductive genetics, and post-translational modification, as well as educators and students covering germline cell biology.