Specificity of the interaction of RocR with the rocG-rocA intergenic region in Bacillus subtilis.

In Bacillus subtilis, expression of the rocG gene, encoding glutamate dehydrogenase, and the rocABC operon, involved in arginine catabolism, requires SigL (sigma(54))-containing RNA polymerase as well as RocR, a positive regulator of the NtrC/NifA family. The RocR protein was purified and shown to bind specifically to the intergenic region located between rocG and the rocABC operon. DNaseI footprinting experiments were used to define the RocR-binding site as an 8 bp inverted repeat, separated by one base pair, forming an imperfect palindrome which is present twice within the rocG-rocABC intergenic region, acting as both a downstream activating sequence (DAS) and an upstream activating sequence (UAS).

ClpP of Streptococcus salivarius is a novel member of the dually regulated class of stress response genes in gram-positive bacteria.

Nucleotide sequence analysis of the Streptococcus salivarius clpP locus revealed potential binding sites for both the CtsR and HrcA repressors. Dual regulation by HrcA and CtsR was demonstrated by using Bacillus subtilis as a heterologous host, and CtsR was shown to bind directly to the clpP promoter sequence. This is the first example of a clpP gene under the control of HrcA.

Regulation of Streptococcus pneumoniae clp genes and their role in competence development and stress survival.

In vitro mariner transposon mutagenesis of Streptococcus pneumoniae chromosomal DNA was used to isolate regulatory mutants affecting expression of the comCDE operon, encoding the peptide quorum-sensing two-component signal transduction system controlling competence development. A transposon insertion leading to increased comC expression was found to lie directly upstream from the S. pneumoniae clpP gene, encoding the proteolytic subunit of the Clp ATP-dependent protease, whose expression in Bacillus subtilis is controlled by the CtsR repressor.

The two-component system ArlS-ArlR is a regulator of virulence gene expression in Staphylococcus aureus.

Staphylococcus aureus is a major human pathogen that produces many virulence factors in a temporally regulated manner controlled by at least two global virulence regulatory loci (agr and sarA). We identified previously a two-component system, ArlS-ArlR, that modifies the activity of extracellular serine protease and may be involved in virulence regulation. Here, we show that mutations in either arlR or arlS increase the production of secreted proteins [alpha-toxin (Hla), beta-haemolysin, lipase, coagulase, serine protease (Ssp)] and especially protein A (Spa).

Regulation of the acetoin catabolic pathway is controlled by sigma L in Bacillus subtilis.

Bacillus subtilis grown in media containing amino acids or glucose secretes acetate, pyruvate, and large quantities of acetoin into the growth medium. Acetoin can be reused by the bacteria during stationary phase when other carbon sources have been depleted. The acoABCL operon encodes the E1alpha, E1beta, E2, and E3 subunits of the acetoin dehydrogenase complex in B.

The CtsR regulator of stress response is active as a dimer and specifically degraded in vivo at 37 degrees C.

CtsR (class three stress gene repressor) negatively regulates the expression of class III heat shock genes (clpP, clpE and the clpC operon) by binding to a directly repeated heptanucleotide operator sequence (A/GGTCAAA NAN A/GGTCAAA). CtsR-dependent genes are expressed at a low level at 37 degrees C and are strongly induced under heat shock conditions. We performed a structure/function analysis of the CtsR protein, which is highly conserved among low G+C Gram-positive bacteria.