RUI: Genetic Analysis of Conjugation in Tetrahymena

嗜热四膜虫是一种淡水纤毛原生动物，非常适合分析与细胞分裂周期和接合(有性繁殖)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，这得益于细胞皮质中形成纤毛化口腔器官的基底的精确控制的增殖和图案化。这一皮质程序与核分裂和胞质分裂相结合，为细胞分裂过程中的发育事件提供了一个容易可视化、细节丰富的“时钟”。这一发育计划为理解核-皮质相互作用的遗传控制提供了独特的机会，通过这种细胞周期主导的格局，核-皮质相互作用调节细胞的进展。有三个特点为发育分析推荐了这个系统：丰富的发育里程碑，携带和表达具有致命表型的突变的能力，以及研究同时针对有丝分裂和减数分裂机制而不影响细胞活力的突变的能力。这个项目的目标有三个：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调查；3)揭示与配偶停滞相关的发育“检查点”的细胞遗传学基础--“星形”细胞系，即中止正常的配偶发育的细胞系。涉及这三种分析方法的工作将揭示嗜热四膜虫性行为发育的遗传基础及其与细胞分裂周期的整合。该项目还将帮助将细胞表面发生的事件与细胞分裂周期中发生在细胞核内的事件联系起来，同时为本科生提供卓越的研究培训体验。

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.