FlgM is a primary regulator of sigma(D) activity, and its absence restores motility to a sinR mutant

We have used mini-Tn10 mutagenesis to identify negative regulators of sigma(D) activity, Nine independent insertions were mapped to five genes: flgM, flgK, fliD, fliS, and fliT, suggesting that FlgM export is regulated similarly in Bacillus subtilis and Salmonella typhimurium. We show that a deletion of flgM can restore sigma(D) activity to a sinR null mutant of B, subtilis, although fla/che operon expression is affected by neither SinR nor FlgM.