Sequence elements determining ampC promoter strength in E. coli.
AUTOR(ES)
Jaurin, B
RESUMO
A number of spontaneous up-promoter mutations have been isolated in the ampC beta-lactamase gene of Escherichia coli. The mutants were analyzed by DNA sequencing, and the level of ampC gene expression was determined. Six mutants with a 21-fold increase in promoter strength compared with the wild-type were mutated in the -35 promoter region from TTGTCA to the consensus sequence TTGACA . The -10 region sequence TACAAT was mutated to the consensus sequence TATAAT in three mutants exhibiting an ampC promoter seven times stronger than the wild-type. We have previously described a 1-bp insertion mutant ( Jaurin et al., 1981) that changes the inter-region distance to the consensus 17 bp. Thus, all the up-mutations found in the ampC promoter represent corrections of the three major discrepancies between the ampC promoter and the consensus E. coli promoter. We conclude that the three consensus elements of E. coli promoters, the -35 and -10 regions and an optimal inter-region distance of 17 bp, are the main elements determining the promoter strength.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=553125Documentos Relacionados
- Identification of a novel ampC beta-lactamase promoter in a clinical isolate of Escherichia coli.
- A promoter probe vector (pJAC4) that utilizes the ampC beta-lactamase gene of Escherichia coli.
- −11 Mutation in the ampC Promoter Increasing Resistance to β-Lactams in a Clinical Escherichia coli Strain
- Identification of the nucleotide sequence recognized by the cAMP-CRP dependent CytR repressor protein in the deoP2 promoter in E. coli.
- AmpC and AmpH, proteins related to the class C beta-lactamases, bind penicillin and contribute to the normal morphology of Escherichia coli.