Lee Crystal, Oh Jeong Su
Department of Integrative Biotechnology, Sungkyunkwan University, 2066 Seobu-ro, Suwon 16419, South Korea.
Nucleic Acids Res. 2025 Jan 11;53(2). doi: 10.1093/nar/gkae1207.
Double-strand breaks (DSBs) are a formidable threat to genome integrity, potentially leading to cancer and various genetic diseases. The prolonged lifespan of mammalian oocytes increases their susceptibility to DNA damage over time. While somatic cells suppress DSB repair during mitosis, oocytes exhibit a remarkable capacity to repair DSBs during meiotic maturation. However, the precise mechanisms underlying DSB repair in oocytes remain poorly understood. Here, we describe the pivotal role of the BRCA1-PLK1-CIP2A axis in safeguarding genomic integrity during meiotic maturation in oocytes. We found that inhibition of homologous recombination (HR) severely impaired chromosome integrity by generating chromosome fragments during meiotic maturation. Notably, HR inhibition impaired the recruitment of CIP2A to damaged chromosomes, and the depletion of CIP2A led to chromosome fragmentation following DSB induction. Moreover, BRCA1 depletion impaired chromosomal recruitment of CIP2A, but not vice versa. Importantly, the impaired chromosomal recruitment of CIP2A could be rescued by PLK1 inhibition. Consequently, our findings not only underscore the importance of the chromosomal recruitment of CIP2A in preventing chromosome fragmentation, but also demonstrate the regulatory role of the BRCA1-PLK1-CIP2A axis in this process during oocyte meiotic maturation.
双链断裂(DSBs)对基因组完整性构成巨大威胁,可能导致癌症和各种遗传疾病。随着时间的推移,哺乳动物卵母细胞较长的寿命增加了它们对DNA损伤的易感性。虽然体细胞在有丝分裂期间抑制DSB修复,但卵母细胞在减数分裂成熟过程中表现出显著的DSB修复能力。然而,卵母细胞中DSB修复的精确机制仍知之甚少。在这里,我们描述了BRCA1-PLK1-CIP2A轴在卵母细胞减数分裂成熟过程中保护基因组完整性的关键作用。我们发现,抑制同源重组(HR)会在减数分裂成熟过程中产生染色体片段,从而严重损害染色体完整性。值得注意的是,HR抑制会损害CIP2A向受损染色体的募集,而CIP2A的缺失会导致DSB诱导后染色体片段化。此外,BRCA1的缺失会损害CIP2A在染色体上的募集,但反之则不然。重要的是,抑制PLK1可以挽救CIP2A在染色体上募集受损的情况。因此,我们的研究结果不仅强调了CIP2A在染色体上的募集对防止染色体片段化的重要性,还证明了BRCA1-PLK1-CIP2A轴在卵母细胞减数分裂成熟过程中的这一过程中的调节作用。