Glutamine synthetase-constitutive mutation affecting the glnALG upstream promoter of Escherichia coli.
The spontaneous gln-76 mutation of Escherichia coli (Osorio et al., Mol. Gen. Genet. 194:114-123, 1984) was previously shown to be responsible for the cis-dominant constitutive expression of the glnA gene in the absence of a glnG-glnF activator system. Nucleotide sequence analysis has now revealed that gln-76 is a single transversion T.A to A.T, an up-promoter mutation affecting the -10 region of glnAp1, the upstream promoter of the glnALG control region. Both, wild-type and gln-76 DNA control regions were cloned into the promoter-probe plasmid pKO1. Galactokinase activity determinations of cells carrying the fused plasmids showed 10-fold more effective expression mediated by gln-76 than by the glnA wild-type control region. Primer extension experiments with RNA from strains carrying the gln-76 control region indicated that the transcription initiation sites were the same in both the gln-76 mutant and the wild type.
León
P
P
Romero
D
D
Garciarrubio
A
A
Bastarrachea
F
F
Covarrubias
A A
AA
D001483:Base Sequence; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005686:Galactokinase / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000235:genetics*; D009154:Mutation; D009876:Operon; D010957:Plasmids; D014158:Transcription, Genetic; D014161:Transduction, Genetic
D005686:Galactokinase; D004262:DNA Restriction Enzymes; D005974:Glutamate-Ammonia Ligase