Maternal CENP-C restores centromere symmetry in mammalian zygotes to ensure proper chromosome segregation
Tower CA, Manske G, Ferrell EL, Anbarci DN, Jorgensen K, Ma B, Aboelenain M, Ranjan R, Chakraborty S, Moritz L, Das A, Boiani M, Black BE, Chavez S, Marsh EE, Shikanov A, Schindler K, Chen X, Hammoud SS. Maternal CENP-C restores centromere symmetry in mammalian zygotes to ensure proper chromosome segregation. bioRxiv [Preprint]. 2025 Jul 28:2025.07.23.666394. doi: 10.1101/2025.07.23.666394. PMID: 40766472; PMCID: PMC12324218.
Abstract
Across metazoan species, the centromere-specific histone variant CENP-A is essential for accurate chromosome segregation, yet its regulation at the parental-to-zygote transition in mammals is poorly understood. To address this, we developed a CENP-A-mScarlet knock-in mouse model, which revealed sex-specific dynamics: mature sperm retains 10% of the CENP-A levels present in MII-oocytes. However, in zygotes prior to the first mitosis, this difference is resolved, using maternally inherited cytoplasmic-CENP-A. Notably, the increase in CENP-A at paternal centromeres is independent of sensing CENP-A asymmetry or the presence of maternal chromosomes. Instead, CENP-A equalization relies on asymmetric recruitment of maternal CENP-C to paternal centromeres. Depletion of maternal CENP-A decreases total CENP-A in pronuclei without disrupting equalization. In contrast, reducing maternal CENP-C or disruption of its dimerization domains impairs CENP-A equalization and chromosome segregation. Therefore, maternal CENP-C acts a key epigenetic regulator that resets centromeric symmetry at fertilization to preserve genome integrity.