title: Alterations upstream from the Shine-Dalgarno region and their effect on bacterial gene expression.
abstract: A vector containing the leftward promoter (pL) as transcription initiation signal and a synthetic, easily adaptable translation initiation region have been constructed. We have used the expression system to assess the relevance of sequences upstream from the Shine-Dalgarno (SD) region in the translational-initiation process. To this end, a series of structural variants of the prototype ribosome-binding site were used to direct the synthesis of both mature human fibroblast interferon and beta-galactosidase (beta-gal). It was found that alterations 5' to the SD element can considerably affect the rate of mRNA translation. The observation that the relative efficiency of the various 5'-untranslated regions depends on the downstream coding information implies that secondary (and/or tertiary) structure formation is of major importance in the initiation process. But an mRNA folding, in which the SD and ATG determinant are set free in single-stranded regions, does not unconditionally guarantee an efficient initiation of translation.
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005796:Genes; D005798:Genes, Bacterial; D005822:Genetic Vectors; D006801:Humans; D007370:Interferon Type I / Q000235:genetics; D009690:Nucleic Acid Conformation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D012270:Ribosomes / Q000378:metabolism; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D007370:Interferon Type I; D012333:RNA, Messenger; D004262:DNA Restriction Enzymes; D001616:beta-Galactosidase