title: A regulatory element within a gene of a ribosomal protein operon of Escherichia coli negatively controls expression by decreasing the translational efficiency.
abstract: The trmD operon of Escherichia coli consists of the genes for the ribosomal protein (r-protein) S16, a 21 kDa protein (21K) of unknown function, the tRNA(m1G37)methyltransferase (TrmD), and r-protein L19, in this order. Previously we have shown that the steady-state amount of the two r-proteins exceeds that of the 21K and TrmD proteins 12- and 40-fold, respectively, and that this differential expression is solely explained by translational regulation. Here we have constructed translational gene fusions of the trmD operon and lacZ. The expression of a lacZ fusion containing the first 18 codons of the 21K protein gene is 15-fold higher than the expression of fusions containing 49 or 72 codons of the gene. This suggests that sequences between the 18th and the 49th codon may act as a negative element controlling the expression of the 21K protein gene. Evidence is presented which demonstrates that this regulation is achieved by reducing the efficiency of translation.
authors.affiliation: Department of Microbiology, University of Umeå, Sweden.
authors.forename: P M
authors.initials: PM
authors.lastname: Wikström
authors.forename: G R
authors.initials: GR
authors.lastname: Björk
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D010957:Plasmids; D014176:Protein Biosynthesis; D012269:Ribosomal Proteins / Q000096:biosynthesis / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D012269:Ribosomal Proteins; D001616:beta-Galactosidase