Department of Clinical Laboratory Medicine of Shanghai Tenth People's Hospital, Tongji University School of Life Sciences and Technology, Shanghai 200092, China.
Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Genet Genomics. 2021 Jan 20;48(1):63-74. doi: 10.1016/j.jgg.2021.01.001. Epub 2021 Feb 9.
Cyclin-dependent kinase 1 (CDK1) plays an essential role in cell cycle regulation. However, as mouse Cdk1 embryos die early, the role of CDK1 in regulating the cell cycle and embryo development remains unclear. Here, we showed that zebrafish cdk1 embryos exhibit severe microphthalmia accompanied by multiple defects in S phase entry, M phase progression, and cell differentiation but not in interkinetic nuclear migration. We identified Top2a as a potential downstream target and cyclin A2 and cyclin B1 as partners of Cdk1 in cell cycle regulation via an in silico analysis. While depletion of either cyclin A2 or Top2a led to the decreased S phase entry in zebrafish retinal cells, the depletion of cyclin B1 led to M phase arrest. Moreover, phosphorylation of Top2a at serine 1213 (S1213) was nearly abolished in both cdk1 and ccna2 mutants, but not in ccnb1 mutants. Furthermore, overexpression of TOP2A, the phosphomimetic form of human TOP2A, rescued S phase entry and alleviated the microphthalmia defects in both cdk1 and ccna2 embryos. Taken together, our data suggest that Cdk1 interacts with cyclin A2 to regulate S phase entry partially through Top2a phosphorylation and interacts with cyclin B1 to regulate M phase progression.
细胞周期蛋白依赖性激酶 1（CDK1）在细胞周期调控中起着至关重要的作用。然而，由于小鼠 Cdk1 胚胎早期死亡，CDK1 在调节细胞周期和胚胎发育中的作用仍不清楚。在这里，我们发现斑马鱼 cdk1 胚胎表现出严重的小眼症，并伴有 S 期进入、M 期进展和细胞分化的多种缺陷，但在核迁移过程中没有缺陷。我们通过计算机分析鉴定出 Top2a 是 CDK1 调节细胞周期的潜在下游靶标，以及 cyclin A2 和 cyclin B1 是 CDK1 的伴侣。虽然敲低 cyclin A2 或 Top2a 都会导致斑马鱼视网膜细胞 S 期进入减少，但敲低 cyclin B1 会导致 M 期停滞。此外，cdk1 和 ccna2 突变体中 Top2a 的丝氨酸 1213（S1213）磷酸化几乎被完全消除，但在 ccnb1 突变体中没有。此外，人源 TOP2A 的磷酸模拟形式 TOP2A 的过表达挽救了 S 期进入，并缓解了 cdk1 和 ccna2 胚胎的小眼症缺陷。总之，我们的数据表明，Cdk1 与 cyclin A2 相互作用以调节 S 期进入，部分通过 Top2a 磷酸化，与 cyclin B1 相互作用以调节 M 期进展。
