HIGH-LEVEL EXPRESSION OF WHIG - A KEY GENE FOR STREPTOMYCES DIFFERENTIATION IN ESCHERICHIA-COLI

Six nucleotides located in the region of translation start site of whi G were changed. whiG was amplified by PCR technique. Reformed sequence s were determined. This gene was directly subcloned into expression ve ctor pET11c containing strong T7 promoter, and the recombinant plasmid was introduced into E. coli BL21(DE3), which could be induced by IPTG to produce T7 RNA polymerase. The SDS-PAGE result showed that whiG hi ghly expressed in E. coli BL21(DE3), and the yield of whiG product was about 20% of insoluble proteins in cell. whiG product (sigma(whiG)) w as further identified by Western blot hybridization after making its a ntibody. whiG gene was subcloned into Streptomyces plasmid pIJ6021, an d then it was introduced into sporulation deficient mutant C71 from St reptomyces coelicolor. The result showed that C71 could restore sporul ation and sigma(whiG) has biological functions.