Open AccessTranslation through an uncDC mRNA secondary structure governs the level of uncC expression in Escherichia coli
Author(s) -
H. Garry Dallmann,
Stanley D. Dunn
Publication year - 1994
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.176.5.1242-1250.1994
Subject(s) - biology , gene , rna , gene expression , messenger rna , protein subunit , microbiology and biotechnology , genetics , translation (biology) , escherichia coli , protein secondary structure , protein biosynthesis , structural gene , biochemistry
Escherichia coli expresses the beta and epsilon subunits of F1F0-ATP synthase at relative levels consistent with the 3:1 (beta/epsilon) stoichiometry in the holoenzyme. The mechanism of translational control of expression of the uncC gene (epsilon subunit) relative to the immediately 5' uncD gene (beta subunit) was examined. Previous expression studies and a computer analysis suggested the presence of an RNA secondary structure including the 3' end of uncD, the uncDC intergenic region, and the uncC Shine-Dalgarno sequence (S. D. Dunn and H. G. Dallmann, J. Bacteriol. 172:2782-2784, 1990). Analysis of in vitro-transcribed RNA by cleavage with RNases T1, V1, and CL3 and by chemical modification with dimethyl sulfate and diethyl pyrocarbonate confirmed a predicted structure. Introduction of premature uncD stop codons inserted 5' of the secondary structure strongly reduced epsilon expression, whereas stop codons inserted at positions within the secondary structure showed smaller effects, indicating that translational control of epsilon synthesis involves partial coupling to beta synthesis. Possible mechanisms by which the RNA secondary structure and the unfolding of this structure by translation of uncD may govern the level of uncC expression are discussed.