부산대학교 도서관

Wild strains ofBacillus subtilisare capable of forming architecturally complex communities of cells known as biofilms. Critical to biofilm formation is theepsoperon, which is believed to be responsible for the biosynthesis of an exopolysaccharide that binds chains of cells together in bundles. We report that transcription ofepsis under the negative regulation of SinR, a repressor that was found to bind to multiple sites in the regulatory region of the operon. Mutations insinRbypassed the requirement in biofilm formation of two genes of unknown function,ylbFandymcA, andsinI, which is known to encode an antagonist of SinR. We propose that these genes are members of a pathway that is responsible for counteracting SinR-mediated repression. We further propose that SinR is a master regulator that governs the transition between a planktonic state in which the bacteria swim as single cells in liquid or swarm in small groups over surfaces, and a sessile state in which the bacteria adhere to each other to form bundled chains and assemble into multicellular communities. [ABSTRACT FROM AUTHOR]