RUI: Genetic Analysis of Conjugation in Tetrahymena

嗜热四膜虫是一种淡水纤毛原生生物，特别适合分析与细胞分裂周期和结合（有性生殖）相关的核和染色体事件。纤毛虫在有丝分裂过程中表现出无与伦比的丰富的发育标志，这是由于在细胞皮层中形成纤毛虫口腔器官的基础体的精确控制增殖和模式。这个皮层程序与核分裂和细胞质分裂相结合，并提供了一个易于可视化的、详细的细胞分裂发育事件的“时钟”。这个发育程序为理解核皮质相互作用的遗传控制提供了独特的机会，核皮质相互作用通过细胞周期主导的景观调节细胞的进程。该系统具有三个特点：丰富的发育标志，携带和表达具有致死表型的突变的能力，以及研究靶向有丝分裂和减数分裂机制的突变而不影响细胞活力的能力。该项目的目标有三个方面：1)建立和筛选一个“反义”文库，以寻找与配偶发育有关的基因；2)对“fenestrin”和其他与原核交换连接相关的蛋白质进行生化研究；3)揭示“明星”细胞系中与配偶阻滞相关的发育“检查点”的细胞遗传学基础，“明星”细胞系中断正常的配偶发育。这三种分析方法的工作将揭示纤毛虫嗜热四膜虫性发育的遗传基础及其与细胞分裂周期的整合。该项目还将有助于将细胞分裂周期中细胞表面发生的事件与细胞核内发生的事件联系起来，同时为本科生提供卓越的研究训练经验。

Tetrahymena thermophila, a freshwater ciliated protist, is uniquely well suited for ana-lysis of nuclear and chromosomal events associated with both the cell division cycle and conjugation (sexual reproduction). Ciliates exhibit an unparalleled richness of developmental landmarks during mitosis by virtue of the precisely controlled proliferation and patterning of basal bodies that form the ciliated oral apparatus in the cell cortex. This cortical program is coupled to both nuclear division and cytokinesis and provides an easily visualized, richly detailed "clock" of developmental events during cell division. This developmental program offers unique opportunities for understanding the genetic control of nuclear-cortical interactions that regulate a cell's progress through this cell-cycle dominated landscape. Three features recommend this system for developmental analysis: a wealth of developmental landmarks, the ability to carry and express mutations with lethal phenotypes, and the ability to study mutations that target both mitotic and meiotic mechanisms without affecting cell viability. The goals of this project are three fold: 1) Build and screen an "antisense" library to search for genes involved in conjugal development, 2) Launch a biochemical investigation into "fenestrin" and other proteins associated with the pronuclear exchange junction, 3) Uncover the cytogenetic basis of the developmental "checkpoint" associated with conjugal arrest in "star"-cell lines that abort normal conjugal development. Work involving these 3 methods of analysis will shed light on the genetic basis of sexual development in the ciliate Tetrahymena thermophila and its integration with the cell division cycle. This project will also help to link events occurring at the cell surface with events occurring within the cell's nucleus during the cell division cycle while providing a superior research training experience for undergraduate students.