Cloning, expression, and catabolite repression of a gene encoding beta-galactosidase of Bacillus megaterium ATCC 14581.
A gene encoding beta-galactosidase, designated mbgA, was isolated from Bacillus megaterium ATCC 14581. Chromosomal beta-galactosidase production could be dramatically induced by lactose but not by isopropyl-beta-D-thiogalactopyranoside (IPTG) and was subject to catabolite repression by glucose. Disruption of mbgA in the B. megaterium chromosome resulted in loss of lactose-inducible beta-galactosidase production. A 27-bp inverted repeat was found to overlap the mbgA promoter sequence. Two partially overlapping catabolite-responsive elements (CREs) were identified within the inverted repeat. Base substitutions within CRE-I and/or CRE-II caused partial relief from catabolite repression. The results suggest that the 27-bp inverted repeat may serve as a target for a catabolite repressor(s).
Institute of Biochemistry, School of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China. gcshaw@nauksrv.ym.edu.tw
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D001410:Bacillus megaterium / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D005947:Glucose / Q000378:metabolism; D007544:Isopropyl Thiogalactoside / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D009154:Mutation; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics*
D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D007544:Isopropyl Thiogalactoside; D001616:beta-Galactosidase; D005947:Glucose; D007785:Lactose