Regulation of the expression of amy TO1 encoding a thermostable alpha-amylase from Streptomyces sp. TO1, in its original host and in Streptomyces lividans TK24.
In its original host, the thermophilic Streptomyces strain sp. TO1, the amy TO1 gene was expressed during growth but only in the presence of starch in the growth medium. When cloned in Streptomyces lividans, on a low copy number replicative plasmid, amy TO1 expression was detectable in fructose-, mannitol- and galactose-grown cultures but not in glucose- or glycerol-grown cultures. This basal expression could be further induced by maltotriose. In a mutant strain of S. lividans disrupted for the LacI-like negative transcriptional regulator (NTR) Reg1, and when the symmetry of the dyadic symmetry element located in the promoter region of amy TO1 was altered, the basal levels of amy TO1 expression were significantly higher than those of the wild-type strain, and the maltotriose inducibility was abolished. These results suggest that, in S. lividans, amy TO1 expression is under the control of the NTR Reg1 due to its interaction with the dyadic symmetry element.
Mellouli
L
L
Centre de Biotechnologie de Sfax, B.P. 'K', 3038, Sfax, Tunisia.
Guerineau
M
M
Bejar
S
S
Virolle
M J
MJ
D001483:Base Sequence; D015152:Blotting, Northern; D003470:Culture Media; D004269:DNA, Bacterial / Q000302:isolation & purification; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D014158:Transcription, Genetic; D014312:Trisaccharides / Q000494:pharmacology; D000516:alpha-Amylases / Q000235:genetics* / Q000378:metabolism
D003470:Culture Media; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D014312:Trisaccharides; C008317:maltotriose; D000516:alpha-Amylases