{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,8,9]],"date-time":"2026-08-09T13:42:53Z","timestamp":1786282973341,"version":"build-2736575974"},"posted":{"date-parts":[[2026,8,9]]},"group-title":"Genetics","reference-count":0,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,8,9]],"date-time":"2026-08-09T00:00:00Z","timestamp":1786233600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Eunice Kennedy Shriver National Institute of Child Health and Human Development","award":["R01HD109322"],"award-info":[{"award-number":["R01HD109322"]}]},{"award":["Investigator Award"],"award-info":[{"award-number":["Investigator Award"]}],"id":[{"id":"https:\/\/ror.org\/006w34k90","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,8,8]]},"abstract":"<jats:p>The small ubiquitin-like modifier SUMO regulates key events of meiosis, including pairing and crossing over between homologous chromosomes. Auto-sumoylation of the SUMO E2-conjugating enzyme UBC9 at lysine 14 alters its substrate selectivity in vitro, but the role of this modification in vivo is unknown. Here, we show that UBC9-K14 auto-sumoylation helps coordinate meiotic prophase and is important for maintenance of the ovarian reserve. Ubc9K14R\/K14R knock-in mice show a variety of defects in meiotic prophase I, including altered assembly of DNA strand-exchange complexes, delayed and defective homolog synapsis, and unstable crossover recombination complexes. In spermatocytes, these defects are associated with reduced efficiency of crossing over between the X and Y chromosomes. Oocytes from Ubc9K14R\/K14R females show related but distinct defects in recombination and synapsis. Moreover, maintenance of the primordial follicle reserve is defective in Ubc9K14R\/K14R females, and their fecundity is reduced. Finally, we identify the meiosis-specific homolog-axis protein SYCP3 as a direct target of UBC9 in vitro and show that SYCP3 modification is strongly stimulated by K14 auto-sumoylation. We infer that auto-sumoylation enables UBC9 to modify a subset of targets in vivo, helping to coordinate key events of meiotic prophase and enhance the survival of primordial follicles to maximize fecundity.<\/jats:p>","DOI":"10.64898\/2026.08.04.742908","type":"posted-content","created":{"date-parts":[[2026,8,9]],"date-time":"2026-08-09T13:25:20Z","timestamp":1786281920000},"source":"Crossref","is-referenced-by-count":0,"title":["Auto-sumoylation of UBC9 coordinates meiotic prophase and protects ovarian reserves"],"prefix":"10.64898","author":[{"given":"Sunkyung","family":"Lee","sequence":"first","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tianhong","family":"Lu","sequence":"additional","affiliation":[{"name":"University of California;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dhananjaya S","family":"Kulkarni","sequence":"additional","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Delin","family":"Zhang","sequence":"additional","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Britney","family":"Ly","sequence":"additional","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sida","family":"Li","sequence":"additional","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Megan","family":"Sarringhaus","sequence":"additional","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yungdae","family":"Ryu","sequence":"additional","affiliation":[{"name":"University of California Davis;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1498-2327","authenticated-orcid":false,"given":"Neil","family":"Hunter","sequence":"additional","affiliation":[{"name":"University of California, Davis"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.08.04.742908","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,9]],"date-time":"2026-08-09T13:25:20Z","timestamp":1786281920000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.08.04.742908"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,9]]},"references-count":0,"URL":"https:\/\/doi.org\/10.64898\/2026.08.04.742908","relation":{},"subject":[],"published":{"date-parts":[[2026,8,9]]},"subtype":"preprint"}}