Streptomyces aureofaciens sporulation-specific sigma factor σ directs expression of a gene encoding protein similar to hydrolases involved in degradation of the lignin-related biphenyl compounds

A previously established method for the identification of promoters recognized by a heterologous RNA polymerase holoenzyme containing a particular sigma factor was used to identify promoters dependent upon a sporulation specific sigma factor, σ^RpoZ, of Streptomyces aureofaciens. Three new positive DNA fragments were identified, and these putative rpoZ-dependent promoters, P_ren24, P_ren57, and P_ren71, contained sequences similar to the consensus sequence of flagellar and chemotaxis promoters. However, only P_ren71 was active in S. aureofaciens. The promoter was induced at the time of aerial mycelium formation, and was inactive in an S. aureofaciens strain with an rpoZ-disrupted gene. The results suggest that the P_ren71 promoter is recognized by an RNA polymerase holoenzyme containing σ^RpoZ in S. aureofaciens. Sequence analysis of the region directed by P_ren71 revealed a gene, ren71, encoding a protein of 358 amino acids with an M_r 37 770. The deduced protein product showed end-to-end sequence similarity to the meta-cleavage compound hydrolase of Sphingomonas paucimobilis.