Silenced Chromatin: Mechanisms of Transcriptional Repression

Lsu Health Sciences Center -Shreveport, Shreveport LA

Investigators

Abstract

This project will use a genetically tractable model organism, baker's yeast, to investigate the molecular events that accompany the process by which genes become dormant ('silenced') and are subsequently re-activated. Yeast genes share many features with those of complex organisms, including a beads-on-a-string structure and many regulatory mechanisms. Shutting off specific genes at the right time and in the right place (i.e., within the proper tissue) is critical for normal development and survival. Understanding the molecular details of how gene expression is shut down is therefore of great interest - all the more so given recent evidence suggesting that the way this happens is remarkably similar in yeast, insects and humans. The goals of this project are: (1) to demonstrate that RNA polymerase, the enzyme responsible for copying the DNA into messenger RNA, is present, but is rendered incapable of working by the specialized chromosomal structure uniquely seen in dormant genes; (2) to characterize the molecular changes that occur when dormant genes become activated in response to an environmental stimulus; and (3) to identify the proteins that assist RNA polymerase in overcoming the 'repressive' effects of dormant gene structure during activation. This project will also provide training for a post-doctoral researcher.