Cloning and analysis of the gene (rpoDA) for the principal sigma factor of Pseudomonas aeruginosa.

A gene (rpoDA) of Pseudomonas aeruginosa whose gene product has a homologous function and structure with the principal sigma factor of Escherichia coli was cloned and sequenced. The DNA region corresponding to one of the two hybridization signals found in P. aeruginosa DNA with a synthetic oligonucleotide probe (rpoD probe) was shown to be able to complement a temperature sensitive mutation of Escherichia coli rpoD gene. The amino acid sequence deduced from the nucleotide sequence of rpoDA showed an extensive homology with that of the principal sigma factor of E. coli throughout the entire region, which indicates that the two gene products have an essentially identical domain structure. A common basic structure observed among principal sigma factors of different eubacterial strains was proposed. RpoDA protein was identified in the extract of the cell carrying a plasmid clone with the rpoDA gene insert by Western blot analysis.