Conditional Sigma Factor Expression, Using the Inducible Acetamidase Promoter, Reveals that the Mycobacterium tuberculosis sigF Gene Modulates Expression of the 16-Kilodalton Alpha-Crystallin Homologue

A chemically inducible acetamidase promoter-sigF fusion gene was integrated into the chromosome of Mycobacterium bovis BCG. Two-dimensional protein gel analysis permitted the identification of a number of protein spots whose expression was SigF related. One spot upregulated by inappropriate induction of sigF expression corresponded to the 16-kDa antigen alpha-crystallin.