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Regulation of the Escherichia coli uncH gene by mRNA secondary structure and translational coupling
Author(s) -
Pati Sushma,
DiSilvestre Deborah,
Brusilow William S. A.
Publication year - 1992
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1992.tb01791.x
Subject(s) - biology , operon , frameshift mutation , gene , messenger rna , microbiology and biotechnology , escherichia coli , gene expression , lac operon , genetics , start codon , regulation of gene expression , mutation
Summary The uncH gene is one of the most poorly‐expressed genes of the proton‐translocating ATPase ( unc ) operon of Escherichia coli. We constructed in‐frame lacZ fusions to uncH and used site‐directed mutagen‐esis to decrease the stability of the putative mRNA secondary structure in the Shine and Dalgarno region for this gene. These mutations significantly increased the expression of uncH. We also used the unc‐lac fusions to show that the insertion of stop codons and a frameshift mutation In uncF , the gene preceding uncH , caused a 10‐fold reduction in uncH expression. Hybridization of total cellular RNA with a lacZ ‐specific probe indicated that transcriptional polarity could not account for the observed decrease in gene expression. These results demonstrate that uncH expression is controlled by mRNA sequences around the translational initiation region, and is translationally coupled to uncF , even in cases where the putative mRNA secondary structure is weakened or eliminated.