Coherent Feedforward Regulation of Gene Expression by Caulobacter σ T and GsrN during Hyperosmotic Stress

Bacteria inhabit diverse niches and must adapt their physiology to constant environmental fluctuations. A major response to environmental perturbation is to change gene expression.Caulobacter and other alphaproteobacteria initiate a complex gene expression program known as the general stress response (GSR) under conditions including oxidative stress, osmotic stress, and nutrient limitation. The GSR enables cell survival in these environments. Understanding how bacteria survive stress requires that we dissect gene expression responses, such as the GSR, at the molecular level. This study is significant, as it defines transcriptional and posttranscriptional layers of gene expression regulation in response to hyperosmotic stress. We further provide evidence that a coherent feedforward motif influences the system properties of theCaulobacter GSR pathway.