Transcriptomes of 35000HP, ΔcpxA, ΔcpxR mutant strains of Haemophilus ducreyi in mid-log, transition, and stationary phase

To better understand the role of H. ducreyi CpxRA in controlling virulence determinants, here we defined genes potentially regulated by CpxRA by using RNA-Seq. Activation of CpxR by deletion of cpxA repressed nearly 70% of its targets, including seven established virulence determinants. Inactivation of CpxR by deletion of cpxR differentially regulated few genes and increased the expression of one virulence determinant. We identified a CpxR binding motif that was enriched in downregulated but not upregulated targets. These data reinforce the hypothesis that CpxA phosphatase activity plays a critical role in controlling H. ducreyi virulence in vivo. Characterization of the downregulated genes may offer new insights into pathogenesis. RNA of Haemophilus ducreyi wildtype, cpxA and cpxR mutants were collected at mid-log, transition, and stationary phases of growth, in quadruplicate.