title: Identification of an amber fragment of the beta subunit of Escherichia coli RNA polymerase: a yardstick for measuring controls on RNA polymerase subunit synthesis.
abstract: An amber fragment of the beta subunit of Escherichia coli RNA polymerase has been recovered from strains carrying the rpoB12 amber mutation, indicating that the B12 mutation resides in the structural gene for the beta subunit. The fragment is readily assayed and can be used to determine the degree of  expression of a single rpoB cistron in strains haploid or diploid for this region. These studies confirm that  the bacterial mechanism, which can compensate for reduced translation of the beta message, operates by the co-ordinate induction of rpoB and rpoC. Furthermore, I show that rpo control depends upon cistron(s) located on the F' factor, KLF10, whose product(s) can act negatively in trans on rpoBC expression.
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000096:biosynthesis*; D004926:Escherichia coli / Q000201:enzymology*; D005144:F Factor; D005796:Genes; D009154:Mutation; D010446:Peptide Fragments / Q000096:biosynthesis*; D014176:Protein Biosynthesis
chemical_list: D010446:Peptide Fragments; D012321:DNA-Directed RNA Polymerases