Genetic and Molecular Analysis of Chromatin Boundaries in Saccharomyces cerevisiae.

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Living organisms must regulate expression of their genes for proper developmental growth and survival. Genes encoded in DNA must be transcribed into RNA, and most are then translated into protein to carry out their functions within cells. But not all genes need to function at all times, so there must be tightly controlled regulation of the transcription and translation processes. One way cells control gene expression is to package DNA-protein into a structure called chromatin, in which the DNA is wrapped around complexes of histones and other proteins that provide a scaffolding for the regulation of their transcription. The goals of this research project are to study how chromatin regulates gene expression at the transcriptional level. The research will use the yeast Saccharomyces cerevisiae, a eukaryotic microbe that allows easier study of cellular functions, while providing information that in most cases can be extrapolated to all eukaryotic cells, even human cells. The major goal of the project is to determine how certain chromatin structures, called heterochromatin, that repress transcription of genetic information, are limited by other structures called boundary elements. Previous research has identified such boundary elements in yeast, and the project will use genetic and molecular analyses to investigate how boundary elements function to prevent heterochromatin from inappropriately repressing genes, and to identify other proteins bound to chromatin that create a boundary element, and how these proteins function to help regulate transcription. The first aim of the project will consist of a genetic screen to identify genes that encode proteins required for the function of a specific boundary element in yeast, followed by a biochemical and molecular analysis of the mechanistic roles of these proteins. The second aim will involve a genetic screen aimed at identifying other yeast DNA sequences that are capable of functioning as boundary elements. These studies will yield a better understanding of the basic processes of transcriptional regulation and provide training opportunities for undergraduate and graduate students, some of them members of underrepresented minorities.