Characterization of a Set of Caulobacter Crescentus Transcription Factors Deletion Strains and Their Role in the Oxidative Stress Response

Abstract

Transcriptional factors control gene expression cascades, often in response to environmental conditions. Here we have investigated the role of these cascades in orchestrating the oxidative stress response in the model system C. crescentus. Expanding the suit of high‐through put tools available in the bacterium, we made a collection of deletions of all the known and predicted transcription factors in the organism and screened these mutants for phenotypes related to general growth defects and the oxidative stress response. We characterized a gene, CC3697 (an OxyR homolog) which regulates the transcriptional response to oxidative stress. Using microarrays, we identified three classes of genes that it regulates as both positive and a negative regulator and used gel shift assays to confirm that some of this transcriptional control was direct. Further characterization of the cascade revealed CosR, a small RNA which facilitates survival during oxidative stress. Thus our collection results shed light on the mechanisms involved in the ability of C.crescentus to adapt to oxidative stress.