RUI: Genetic Analysis of Conjugation in Tetrahymena

Saint Olaf College, Northfield MN

Investigators

Abstract

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.