Cip1, a CDK regulator, determines heterothallic mating or homothallic selfing in a protist

• 成果类型: Article
• 署名作者: Ma, Yang; Yan, Guanxiong; Zhang, Jing; Xiong, Jie; Miao, Wei
• 署名单位: Chinese Academy of Sciences; Institute of Hydrobiology, CAS; Chinese Academy of Sciences; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Chinese Academy of Sciences; Hubei Hongshan Laboratory; Chinese Academy of Sciences; Institute of Hydrobiology, CAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10489
• DOI: 10.1073/pnas.2315531121
• 发表日期: 2024-03-26
• 关键词: sexual reproduction; tetrahymena-thermophila; EVOLUTION; incompatibility; TRANSFORMATION; cycle; diversification; conjugation; expression; pheromone

摘要

Mating type (sex) plays a crucial role in regulating sexual reproduction in most extant eukaryotes. One of the functions of mating types is ensuring self- incompatibility to some extent, thereby promoting genetic diversity. However, heterothallic mating is not always the best mating strategy. For example, in low- density populations or specific environments, such as parasitic ones, species may need to increase the ratio of potential mating partners. Consequently, many species allow homothallic selfing (i.e., self- fertility or intraclonal mating). Throughout the extensive evolutionary history of species, changes in environmental conditions have influenced mating strategies back and forth. However, the mechanisms through which mating - type recognition regulates sexual reproduction and the dynamics of mating strategy throughout evolution remain poorly understood. In this study, we show that the Cip1 protein is responsible for coupling sexual reproduction initiation to mating - type recognition in the protozoal eukaryote Tetrahymena thermophila. Deletion of the Cip1 protein leads to the loss of the selfing- avoidance function of mating - type recognition, resulting in selfing without mating - type recognition. Further experiments revealed that Cip1 is a regulatory subunit of the Cdk19-Cyc9 complex, which controls the initiation of sexual reproduction. These results reveal a mechanism that regulates the choice between mating and selfing. This mechanism also contributes to the debate about the ancestral state of sexual reproduction.