Noise in Gene Expression Determines Cell Fate in Bacillus subtilis

• Published in: Science (American Association for the Advancement of Science) Vol. 317; no. 5837; pp. 526 - 529
• Main Authors: Maamar, Hédia, Raj, Arjun, Dubnau, David
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 27.07.2007
• Subjects: Bacillus subtilis - genetics; Bacillus subtilis - growth & development; Bacillus subtilis - metabolism; Bacillus subtilis - physiology; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological Evolution; Feedback, Physiological; Gene Expression Regulation, Bacterial; Promoter Regions, Genetic; Protein Biosynthesis; RNA Stability; RNA, Bacterial - genetics; RNA, Bacterial - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Stochastic Processes; Transcription Factors - genetics; Transcription Factors - metabolism; Transformation, Bacterial
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1140818

Random cell-to-cell variations in gene expression within an isogenic population can lead to transitions between alternative states of gene expression. Little is known about how these variations (noise) in natural systems affect such transitions. In Bacillus subtilis, noise in ComK, the protein that regulates competence for DNA uptake, is thought to cause cells to transition to the competent state in which genes encoding DNA uptake proteins are expressed. We demonstrate that noise in comK expression selects cells for competence and that experimental reduction of this noise decreases the number of competent cells. We also show that transitions are limited temporally by a reduction in comK transcription. These results illustrate how such stochastic transitions are regulated in a natural system and suggest that noise characteristics are subject to evolutionary forces.