e., a ΔCHL strain) may help

to not only further define the σB regulon, but also allow for further refinement of genes and proteins co-regulated by multiple alternative σ factors. Regulatory redundancy among multiple alternative σ factors has also previously been demonstrated through analyses of Bacillus subtilis alternative σ factor mutants; in particular, certain phenotypes displayed by a B. subtilis triple alternative σ factor deletion mutant were not found among single or double mutants of each of the three alternative σ factors, suggesting regulatory overlaps [29]. Figure 2 Venn diagram of proteins identified as showing higher protein levels in comparisons of (i) L. monocytogenes Selleckchem Berzosertib parent strain 10403S ( PAR .) and Δ BCHL ; (ii) Δ BCH and Δ BCHL ( identifying genes positively regulated by σ L ); Δ BCL and Δ BCHL ( identifying genes positively regulated by σ H ); and Δ BHL and Δ BCHL ( identifying genes positively regulated by σ C ) . Twelve of the 29 proteins that were found to be positively regulated in the parent strain were also found to be positively 10058-F4 order regulated by σB in a recent proteomics study, which compared L. monocytogenes parent strain 10403S and a ΔsigB mutant [23]; these proteins include Lmo2748, Lmo2213, Lmo2158, Lmo2047,

Lmo1830, Lmo0913, Lmo0796, Lmo0794, Lmo0722, Lmo0654, Lmo0539, and Lmo0265. The 17 proteins that show higher levels in the parent strain as compared to the ΔBCHL strain, but were not identified as positively regulated by any of the alternative σ factors include Lmo1540, Lmo2610, Lmo1422, Lmo1421, Lmo1602, Lmo1426, Lmo1428, Lmo2205, Lmo2398, Lmo1601, Lmo0554, Lmo1634, Lmo0110, Lmo2558,

Lmo0783, Lmo0134, and Lmo0098. Table 4 Proteins found to be differentially regulated by at least two of the three alternative sigma factors studied here   Regulation byb Regulation by σBc Differential levels in comparison between parent and ΔBCHL Urease Proteina σH σL σC Lmo0027 + – NDR NDR – Lmo0096 (MptA) + + + NDR + Lmo0319 (BglA) + – NDR NDR – Lmo1877 (Fhs) – - NDR NDR – Lmo2006 (AlsS) + + NDR NDR + Lmo2094 – - – NDR – Lmo2097 – - NDR NDR – Lmo2098 – - NDR NDR NDR PF-6463922 aWhere available, protein name is shown in parenthesis. bProteins that were identified here as positively (+) or negatively (−) regulated (absolute FC > 1.5; p < 0.05) by a given σ factor are shown; NDR (“not differentially regulated”) indicates that a protein was not found to be differentially regulated between strains with and without a given alternative σ factor. cData for proteins differentially regulated by σB were obtained from Mujahid et al. [23]; this study compared protein levels between the 10403S parent strain and an isogenic ΔsigB strain.