Cyc17, a meiosis-specific cyclin, is essential for anaphase initiation and chromosome segregation in <i>Tetrahymena thermophila</i>

Although the role of cyclins in controlling nuclear division is well established, their function in ciliate meiosis remains unknown. In ciliates, the cyclin family has undergone massive expansion which suggests that diverse cell cycle systems exist, and this warrants further investigation. A screen for cyclins in the model ciliate <i>Tetrahymena thermophila</i> showed that there are 34 cyclins in this organism. Only 1 cyclin, Cyc17, contains the complete cyclin core and is specifically expressed during meiosis. Deletion of <i>CYC17</i> led to meiotic arrest at the diakinesis-like metaphase I stage. Expression of genes involved in DNA metabolism and chromosome organization (chromatin remodeling and basic chromosomal structure) was repressed in <i>cyc17</i> knockout matings. Further investigation suggested that Cyc17 is involved in regulating spindle pole attachment, and is thus essential for chromosome segregation at meiosis. These findings suggest a simple model in which chromosome segregation is influenced by Cyc17.

尽管细胞周期蛋白（cyclins）在调控核分裂中的作用已有明确定论，但其在纤毛虫（ciliate）减数分裂中的功能仍未阐明。在纤毛虫中，细胞周期蛋白家族发生了大规模扩增，这暗示该类生物存在多样化的细胞周期系统，亟需开展深入研究。针对模式纤毛虫嗜热四膜虫（Tetrahymena thermophila）开展的细胞周期蛋白筛选实验显示，该生物体内共存在34种细胞周期蛋白。其中仅Cyc17这一种细胞周期蛋白含有完整的细胞周期蛋白核心结构，且仅在减数分裂过程中特异性表达。敲除CYC17会导致减数分裂阻滞于类终变期的减数分裂I中期。在cyc17敲除的交配组合中，参与DNA代谢与染色体组织（包括染色质重塑及基础染色体结构）的基因表达均受到抑制。进一步研究表明，Cyc17参与调控纺锤体极附着过程，因此对减数分裂中的染色体分离至关重要。上述研究结果提出了一个简化模型，即染色体分离过程受Cyc17调控。

搜集汇总

背景与挑战

背景概述

该数据集聚焦于嗜热四膜虫中的减数分裂特异性cyclin蛋白Cyc17，研究其功能。关键发现包括Cyc17是唯一包含完整cyclin核心且减数分裂特异性表达的蛋白，其缺失导致减数分裂停滞在中期I阶段，并影响染色体分离相关基因的表达，揭示了Cyc17在调控纺锤体附着和染色体分离中的重要作用。数据集包含实验数据和补充材料，支持细胞周期和减数分裂机制的研究。