The Decades-Long Dormancy of REC8 Cohesin
Egg cells begin meiosis during the fetal period of a person with ovaries, remaining dormant after their birth until ovulation potentially decades later. Throughout this period, a protein complex known as REC8 cohesin acts as a molecular glue, holding chromosomes together. These bonds gradually weaken with age, increasing the likelihood of errors when chromosomes separate during cell division and potentially helping explain why fertility in those who ovulate declines with age.
Isolating OMC1 in Murine Models
Published in Nature Aging on Thursday, a collaborative finding by teams from Chiba University, Kumamoto University, and the Riken research institute identifies the protein OMC1 as playing a crucial role in maintaining the bonds between chromosomes in egg cells throughout reproductive life. Researchers used mice to discover that OMC1 helps prevent REC8 cohesin from declining, allowing chromosomes to remain properly connected.
Mutation Analysis and Genetic Deletion Tests
Genetically removing OMC1 caused young mice to exhibit chromosome abnormalities resembling those typically seen in older eggs. Furthermore, embryos produced from eggs lacking OMC1 were less likely to develop normally after fertilization. Conversely, when researchers artificially reintroduced OMC1 into deficient eggs, premature chromosome separation was suppressed.
Investigating the CCDC201 Variant Link
The team also investigated a mutation corresponding to one in the human gene CCDC201. Research published in 2024 revealed that individuals who undergo ovulation and possess a pair of a specific CCDC201 gene variant reached menopause about nine years sooner than peers.
Future Fertility Technology Implications and Study Limitations
Speaking to journalists at a Thursday news conference, Chiba University Graduate School of Medicine professor Keiichiro Ishiguro—who spearheaded the study—stated that identifying this protein might one day help pave the way for methods designed to stop egg quality from deteriorating with age. Even so, the research team noted important limitations, as the findings are based primarily on experiments in mice. Additional studies are necessary to confirm if the protein functions identically in human eggs and to determine whether these findings can translate to fertility therapies, according to the researchers.
