Structure and function of saw1--a gene related to differentiation of Streptomyces ansochromogenes

The DNA sequence of double strands of saw1 gene was determined by the method of chaintermination inhibitors. The result indicated that the 1500 bp of DNA fragment displayed a complete open reading frame (ORF), the encoding regions were located in 419 to 1252 bp positions, saw1 product has 89% identity to amino acids of sigma whiG of Streptomyces coelicolor. When recombinant plasmid containing a 1500 bp saw1 DNA fragment insert in plasmid pIJ702 was introduced into Streptomyces coelicolor C71, the sporulation deficient mutant C71 could form spore and produce grey pigment. The gene function was studied by using the method of gene disruption and the result showed that the saw1 played an important role in developmental changes from aerial hypha to spore formation of Streptomyces ansochromogenes.