Construction of alpha-amylase-producing strains not subject to carbon catabolite repression.
The dyatic symmetric element (DSE) present in the alpha-amylase gene promoter region of the thermophilic Streptomyces strain sp. TO1, and the whole alpha-amylase gene (amy TO1) with a 3-bp change in the DSE, were cloned in the high copy number replicative cloning vector pIJ702 giving pLM10 and pLM11 plasmids respectively. In TO1/pLM10 and Streptomyces lividans TK24/pLM11 strains, the expression of alpha-amylase TO1 gene became insensible to the negative effect of glucose and glycerol. These results strongly suggest that, in a high copy number system, the negative transcriptional regulator was titrated out by the DSE and the repression of the expression of amy TO1 gene is abolished.
Mellouli
Lotfi
L
Centre de Biotechnologie de Sfax, P.O. Box K 3038, Sfax, Tunisia. lotfi.mallouli@cbs.rnrt.tn
Karray-Rebai
Ines
I
Bejar
Samir
S
D003001:Cloning, Molecular; D004794:Enzyme Repression; D018628:Gene Dosage; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005822:Genetic Vectors; D005947:Glucose / Q000494:pharmacology; D005990:Glycerol / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics*; D000516:alpha-Amylases / Q000096:biosynthesis / Q000235:genetics*
D000516:alpha-Amylases; D005947:Glucose; D005990:Glycerol