Regulation of β-Galactosidase Expression in Bacillus megaterium DSM319 by a XylS/AraC-Type Transcriptional Activator

The β-galactosidase-encoding bgaM gene of Bacillus megaterium DSM319 and the divergently orientated bgaR operon were isolated and sequenced. Both traits are subject to catabolite repression. A set of single-gene replacement mutants was generated and used to analyze gene function. BgaR was found to be a XylS/AraC-type positive transcriptional regulator of bgaM; a potential regulator binding site overlaps the bgaM promoter. A mechanism for regulation of β-galactosidase expression in B. megaterium is proposed.