Molecular level stochastic model for competence cycles in Bacillus subtilis.
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.
Schultz
Daniel
D
Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, CA 92093-0374, USA. schultz@ucsd.edu
Ben Jacob
Eshel
E
Onuchic
José N
JN
Wolynes
Peter G
PG
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
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D014157:Transcription Factors; C087449:comK protein, Bacillus subtilis