Stochastic Pulse Regulation in Bacterial Stress Response

• DOI: 10.1126/science.1208144
• Publication Date: 2011-10-07T04:27:24Z
• Authors: James C. W. Locke; Jonathan W. Young; Michelle Fontes; María Jesús Herná...; Michael B. Elowitz
• Keywords: Feedback, Physiological; 570; Stochastic Processes; 0303 health sciences; Transcription, Genetic; Sigma Factor; Gene Expression Regulation, Bacterial; Mycophenolic Acid; Protein Serine-Threonine Kinases; Phosphoric Monoester Hydrolases; 03 medical and health sciences; Bacterial Proteins; Stress, Physiological; Gene Regulatory Networks; Phosphorylation; Carrier Proteins; Bacillus subtilis

Gene regulatory circuits can use dynamic, and even stochastic, strategies to respond environmental conditions. We examined activation of the general stress response mediated by alternative sigma factor, σ(B), in individual Bacillus subtilis cells. observed that energy activates σ(B) discrete stochastic pulses, with increasing levels leading higher pulse frequencies. By perturbing rewiring endogenous system, we found this behavior results from three key features circuit: an ultrasensitive phosphorylation switch; stochasticity ("noise"), which a mixed (positive negative) transcriptional feedback, both amplify switch it off. Together, these show how prokaryotes encode signals using frequency modulation through compact architecture.