Disease relevance of rpoA

• The rpoA gene specifies a protein of 339 amino acids with deduced molecular mass of 36,510 Da, exhibiting 64.3 and 70.7% similarity over its entire length to Escherichia coli and B. subtilis alpha subunits, respectively [1].
• The rpoA gene, encoding the alpha subunit of RNA polymerase, was cloned from Streptomyces coelicolor A3(2) [1].
• The Salmonella typhimurium phs chromosomal locus essential for the reduction of thiosulfate to hydrogen sulfide was cloned, and some features of its regulation were examined [2].

High impact information on rpoA

• We isolated two rpoD mutants with such properties, but no rpoA mutant with similar properties [3].
• DNA sequence determination of several 'Lac-' mutant rpoA genes revealed that all had mutations clustered within a short segment near the C-terminus of alpha, between amino acid residues 265 and 270 [4].
• This mutation was mapped by marker rescue to within a 182bp region near the 3' end of rpoA and was subsequently transferred to a plasmid by recombination in vivo [5].
• The rpoA341 (phs) mutation of Escherichia coli results in decreased expression of several positively regulated operons and has been mapped to within or very near the rpoA gene encoding the alpha subunit of RNA polymerase [5].
• We have shown that plasmid-directed synthesis of the wild-type alpha subunit can complement the defective phenotypes associated with this mutation consistent with its proposed location within rpoA [5].

Chemical compound and disease context of rpoA

• The phs locus conferred H2S production on Escherichia coli, suggesting that it contains the structural gene for thiosulfate reductase [2].
• The genes for 1,2-propanediol degradation (pdu) and B12 synthesis (cob), along with the genes for sulfur reduction (ttr, phs, and asr), constitute more than 1% of the Salmonella genome and are all absent from E. coli [6].

Biological context of rpoA

• Nucleotide sequence of the rpoA-rplQ DNA of Escherichia coli: a second regulatory binding site for protein S4 [7]?
• All four mutations have been mapped to the genes of the alpha operon and have been assigned tentatively to the gene rpoA, which specifies the alpha subunit of RNA polymerase [8].
• The mutations were found to be responsible for the temperature-sensitive growth by complementation test using a rpoA-expression plasmid [9].
• The chloroplast genome contains sequences homologous to the Escherichia coli rpoA, rpoB and rpoC genes [10].
• We have employed a reporter plasmid system to screen other, previously described, rpoA mutants for effects on activation of a P2 late promoter and have identified a second allele, rpoA155, that blocks P2 late transcription [11].

Anatomical context of rpoA

• The plastid rpoA gene encoding a protein homologous to the bacterial RNA polymerase alpha subunit is expressed in pea chloroplasts [12].

Associations of rpoA with chemical compounds

• Both the mutant rpoA genes were found to carry a single base transition which leads to a substitution of Cys for Arg at the position 191 (rpoA101) or 45 (rpoA112), respectively [9].
• We have shown that a second mutation to auxotrophy, cymX, which is satisfied by either methionine or cysteine, is closely linked to phs [13].

Other interactions of rpoA

• The rpoA-rplQ intercistronic region shows strong primary, and potential secondary structural homologies with the S4-binding sites on 16S rRNA and S13 mRNA [7].
• A lacZ-rpoA gene-fusion has been constructed and expressed in E. coli [12].

Analytical, diagnostic and therapeutic context of rpoA

• Sequence analysis of two temperature-sensitive mutations in the alpha subunit gene (rpoA) of Escherichia coli RNA polymerase [9].
• Northern blot analysis has shown that rpoA is co-transcribed with the gene for ribosomal protein S11 [12].

References