title: Small regulatory RNA-induced growth rate heterogeneity of Bacillus subtilis.
abstract: Isogenic bacterial populations can consist of cells displaying heterogeneous physiological traits. Small regulatory RNAs (sRNAs) could affect this heterogeneity since they act by fine-tuning mRNA or protein levels to coordinate the appropriate cellular behavior. Here we show that the sRNA RnaC/S1022 from the Gram-positive bacterium Bacillus subtilis can suppress exponential growth by modulation of the transcriptional regulator AbrB. Specifically, the post-transcriptional abrB-RnaC/S1022 interaction allows B. subtilis to increase the cell-to-cell variation in AbrB protein levels, despite strong negative autoregulation of the abrB promoter. This behavior is consistent with existing mathematical models of sRNA action, thus suggesting that induction of protein expression noise could be a new general aspect of sRNA regulation. Importantly, we show that the sRNA-induced diversity in AbrB levels generates heterogeneity in growth rates during the exponential growth phase. Based on these findings, we hypothesize that the resulting subpopulations of fast- and slow-growing B. subtilis cells reflect a bet-hedging strategy for enhanced survival of unfavorable conditions.
authors: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors: Ruben A T
authors: RA
authors: Mars
authors: INRA, UR1077, Mathématique Informatique et Génome, Jouy-en-Josas, France.
authors: Pierre
authors: P
authors: Nicolas
authors: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors: Mariano
authors: M
authors: Ciccolini
authors: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors: Ewoud
authors: E
authors: Reilman
authors: Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
authors: Alexander
authors: A
authors: Reder
authors: Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
authors: Marc
authors: M
authors: Schaffer
authors: Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
authors: Ulrike
authors: U
authors: Mäder
authors: Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany.
authors: Uwe
authors: U
authors: Völker
authors: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors: Jan Maarten
authors: JM
authors: van Dijl
authors: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors: Emma L
authors: EL
authors: Denham
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018740:Genetic Heterogeneity; D011401:Promoter Regions, Genetic; D012313:RNA / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: C060762:AbrB protein, Bacillus subtilis; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D012313:RNA