Molecular Mechanism of DksA

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

Transcription of genomic DNA into messenger RNA by RNA polymerase is the first step of gene expression, and is extensively controlled in all living organisms. The goal of this project is to understand the molecular mechanism by which a global transcriptional regulator DksA controls the bacterial response to starvation and stress. During starvation, DksA acts in concert with the alarmone ppGpp and to couple the ribosomal RNA transcription, and thus ribosome production, to the cellular demand for protein synthesis. The mechanism of the DksA action is very unusual: unlike most transcription initiation factors, DksA does not recognize a specific DNA sequence and instead directly binds to RNA polymerase near the enzyme's active site to alter the structure and the stability of transcription complexes. In this work, the Artsimovitch laboratory will dissect DksA interactions with RNA polymerase, investigate DksA effects on transcription elongation and termination, and test whether DksA alters the fidelity of RNA synthesis. Since DksA appears to exert its control near the RNA polymerase active site, whose structure and basic mechanism are universally conserved in all domains of life, the paradigms established by this analysis will have far-reaching implications. The broader impact of this project lies in its education and dissemination emphases. The activities will contribute to the training of graduate and undergraduate students who will receive broad multi-disciplinary training in structure/function analysis of a transcription regulator. The project will also generate tools for a laboratory course in microbial genetics and resource materials for other research groups around the world.