title: Molecular level stochastic model for competence cycles in Bacillus subtilis.
abstract: The role of stochasticity and noise in controlling genetic circuits is investigated in the context of transitions into and from competence in Bacillus subtilis. Recent experiments have demonstrated that bistability is not necessary for this function, but that the existence of one stable fixed point (vegetation) and an excitable unstable one (competence) is sufficient. Stochasticity therefore plays a crucial role in this excitation. Noise can be generated by discrete events such as RNA and protein synthesis and their degradation. We consider an alternative noise source connected with the protein binding/unbinding to the DNA. A theoretical model that includes this "nonadiabatic" mechanism appears to produce a better agreement with experiments than models where only the adiabatic limit is considered, suggesting that this nonconventional stochasticity source may be important for biological functions.
authors.affiliation: Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, CA 92093-0374, USA. schultz@ucsd.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Schultz
authors.forename: Eshel
authors.initials: E
authors.lastname: Ben Jacob
authors.forename: José N
authors.initials: JN
authors.lastname: Onuchic
authors.forename: Peter G
authors.initials: PG
authors.lastname: Wolynes
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development*; D001426:Bacterial Proteins / Q000235:genetics; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics; D008954:Models, Biological; D008958:Models, Molecular; D013269:Stochastic Processes; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D014157:Transcription Factors; C087449:comK protein, Bacillus subtilis