College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
Cell Prolif. 2020 Oct;53(10):e12895. doi: 10.1111/cpr.12895. Epub 2020 Sep 10.
DNA damage and errors of accurate chromosome segregation lead to aneuploidy and foetal defects. DNA repair and the spindle assembly checkpoint (SAC) are the mechanisms developed to protect from these defects. Checkpoint kinase 1 (CHK1) is reported to be an important DNA damage response protein in multiple models, but its functions remain unclear in early mouse embryos.
Immunofluorescence staining, immunoblotting and real-time reverse transcription polymerase chain reaction were used to perform the analyses. Reactive oxygen species levels and Annexin-V were also detected.
Loss of CHK1 activity accelerated progress of the cell cycle at the first cleavage; however, it disturbed the development of early embryos to the morula/blastocyst stages. Further analysis indicated that CHK1 participated in spindle assembly and chromosome alignment, possibly due to its regulation of kinetochore-microtubule attachment and recruitment of BubR1 and p-Aurora B to the kinetochores, indicating its role in SAC activity. Loss of CHK1 activity led to embryonic DNA damage and oxidative stress, which further induced early apoptosis and autophagy, indicating that CHK1 is responsible for interphase DNA damage repair.
Our results indicate that CHK1 is a key regulator of the SAC and DNA damage repair during early embryonic development in mice.
DNA 损伤和染色体分离错误会导致非整倍体和胎儿缺陷。DNA 修复和纺锤体装配检查点（SAC）是为防止这些缺陷而开发的机制。有报道称，检查点激酶 1（CHK1）是多种模型中重要的 DNA 损伤反应蛋白，但在早期小鼠胚胎中其功能仍不清楚。
采用免疫荧光染色、免疫印迹和实时逆转录聚合酶链反应进行分析。还检测了活性氧水平和 Annexin-V。
CHK1 活性丧失加速了第一次卵裂时细胞周期的进展；然而，它扰乱了早期胚胎向桑椹胚/囊胚阶段的发育。进一步的分析表明，CHK1 参与了纺锤体的组装和染色体的排列，这可能是由于它调节着动粒-微管的附着，并募集 BubR1 和 p-Aurora B 到动粒上，表明其在 SAC 活性中的作用。CHK1 活性丧失导致胚胎 DNA 损伤和氧化应激，进一步诱导早期细胞凋亡和自噬，表明 CHK1 负责细胞间 DNA 损伤修复。
我们的结果表明，CHK1 是小鼠早期胚胎发育过程中 SAC 和 DNA 损伤修复的关键调节剂。
