title: Cloning and characterization of the str operon and elongation factor Tu expression in Bacillus stearothermophilus.
abstract: The complete primary structure of the str operon of Bacillus stearothermophilus was determined. It was established that the operon is a five-gene transcriptional unit: 5'-ybxF (unknown function; homology to eukaryotic ribosomal protein L30)-rpsL (S12)-rpsG (S7)-fus (elongation factor G [EF-G])-tuf (elongation factor Tu [EF-Tu])-3'. The main operon promoter (strp) was mapped upstream of ybxF, and its strength was compared with the strength of the tuf-specific promoter (tufp) located in the fus-tuf intergenic region. The strength of the tufp region to initiate transcription is about 20-fold higher than that of the strp region, as determined in chloramphenicol acetyltransferase assays. Deletion mapping experiments revealed that the different strengths of the promoters are the consequence of a combined effect of oppositely acting cis elements, identified upstream of strp (an inhibitory region) and tufp (a stimulatory A/T-rich block). Our results suggest that the oppositely adjusted core promoters significantly contribute to the differential expression of the str operon genes, as monitored by the expression of EF-Tu and EF-G.
authors.affiliation: Department of Protein Biosynthesis, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 166 37 Prague 6, Czech Republic.
authors.forename: L
authors.initials: L
authors.lastname: Krásný
authors.forename: T
authors.initials: T
authors.lastname: Vacík
authors.forename: V
authors.initials: V
authors.lastname: Fucík
authors.forename: J
authors.initials: J
authors.lastname: Jonák
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D005809:Genes, Regulator; D005822:Genetic Vectors; D001411:Geobacillus stearothermophilus / Q000235:genetics*; D008969:Molecular Sequence Data; D009876:Operon; D020653:Peptide Elongation Factor G / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic
chemical_list: D020653:Peptide Elongation Factor G; D010444:Peptide Elongation Factor Tu