Table 1

In vivo overexpression of yczA completely abolishes TRAP regulation of trp operon expression.yczA overexpression was achieved by cloning yczAinto the B. subtilis replicative plasmid pDG148, immediately downstream of the IPTG-inducible spac promoter. B. subtilis strains carrying a trppromoter-leader-trpE-lacZ fusion (15) were transformed with different plasmids and β-galactosidase assays were performed, with and without IPTG addition. ΔmtrB, strain with a deletion of mtrB, the TRAP structural gene (7); pDG148, parental plasmid with no insert (control); pDGyczA, plasmid with a wild-type yczA insert; pDGSTOPyczA, plasmid with a yczA insert in which a stop codon replaces the yczA start codon.

Genetic background Plasmidβ-Galactosidase activity (Miller units)
−Trp +Trp+IPTG
Wild typepDG14814<115<1
Wild typepDGyczA 121508477
Wild typepDGSTOPyczA 10<110<1
ΔmtrB pDG148548512625668
ΔmtrB pDGyczA 658609588621