Yan Guan-Xiong, Zhang Jing, Shodhan Anura, Tian Miao, Miao Wei
a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.
b University of Chinese Academy of Sciences , Beijing , People's Republic of China.
Cell Cycle. 2016 Sep 16;15(18):2506-14. doi: 10.1080/15384101.2016.1207838. Epub 2016 Jul 15.
Meiosis is an important process in sexual reproduction. Meiosis initiation has been found to be highly diverse among species. In yeast, it has been established that cyclin-dependent kinases (Cdks) and cyclins are essential components in the meiosis initiation pathway. In this study, we identified 4 Cdks in the model ciliate, Tetrahymena thermophila, and we found one of them, Cdk3, which is specifically expressed during early conjugation, to be essential for meiosis initiation. Cdk3 deletion led to arrest at the pair formation stage of conjugation. We then confirmed that Cdk3 acts upstream of double-strand break (DSB) formation. Moreover, we detected that Cdk3 is necessary for the expression of many genes involved in early meiotic events. Through proteomic quantification of phosphorylation, co-expression analysis and RNA-Seq analyses, we identified a conjugation-specific cyclin, Cyc2, which most likely partners with Cdk3 to initiate meiosis.
减数分裂是有性生殖中的一个重要过程。减数分裂起始在物种间差异很大。在酵母中，细胞周期蛋白依赖性激酶（Cdks）和细胞周期蛋白已被证实是减数分裂起始途径中的关键成分。在本研究中，我们在模式纤毛虫嗜热四膜虫中鉴定出4种Cdk，发现其中一种Cdk3在接合早期特异性表达，对减数分裂起始至关重要。Cdk3缺失导致在接合配对形成阶段停滞。然后我们证实Cdk3在双链断裂（DSB）形成上游起作用。此外，我们检测到Cdk3对许多参与减数分裂早期事件的基因表达是必需的。通过磷酸化蛋白质组定量、共表达分析和RNA测序分析，我们鉴定出一种接合特异性细胞周期蛋白Cyc2，它很可能与Cdk3协同启动减数分裂。
