TY - JOUR
T1 - Transcription of the Staphylococcus aureus cid and lrg Murein Hydrolase Regulators Is Affected by Sigma Factor B
AU - Rice, Kelly C.
AU - Patton, Toni
AU - Yang, Soo Jin
AU - Dumoulin, Alexis
AU - Bischoff, Markus
AU - Bayles, Kenneth W.
PY - 2004/5
Y1 - 2004/5
N2 - The Staphylococcus aureus lrg and cid loci are homologous operons that have been shown to regulate murein hydrolase activity and affect sensitivity to penicillin. Although the mode of action of these operons has not been demonstrated, a model based on the similarities of the lrgA and cidA gene products to the bacteriophage holin family of proteins has been proposed. In this study, the transcription organization and regulation of these operons were examined by Northern blot analyses. Unexpectedly, cidB and a gene located immediately downstream, designated cidC, were found to be cotranscribed on a 2.7-kb transcript. Maximal cidBC transcription occurred during early exponential growth, and high-level transcription of cidBC was dependent on the rsbU-mediated activation of the alternative sigma factor B (CrB). In contrast, IrgAB transcription in stationary phase was negatively regulated by σ B. Although cidABC transcription was not detected by Northern blot analysis, reverse transcriptase PCR revealed that these genes are also cotranscribed as a single RNA message in early exponential growth. Primer extension analysis revealed the presence of two cidBC transcription start sites, but no apparent σB-dependent promoter consensus sequence was identified in these regions. The rsbU gene was also shown to have a positive impact on murein hydrolase activity but a negligible effect on sensitivity to penicillin-induced killing. These results suggest that the lrgAB and cidBC genes may be part of the S. aureus σB-controlled stress regulon.
AB - The Staphylococcus aureus lrg and cid loci are homologous operons that have been shown to regulate murein hydrolase activity and affect sensitivity to penicillin. Although the mode of action of these operons has not been demonstrated, a model based on the similarities of the lrgA and cidA gene products to the bacteriophage holin family of proteins has been proposed. In this study, the transcription organization and regulation of these operons were examined by Northern blot analyses. Unexpectedly, cidB and a gene located immediately downstream, designated cidC, were found to be cotranscribed on a 2.7-kb transcript. Maximal cidBC transcription occurred during early exponential growth, and high-level transcription of cidBC was dependent on the rsbU-mediated activation of the alternative sigma factor B (CrB). In contrast, IrgAB transcription in stationary phase was negatively regulated by σ B. Although cidABC transcription was not detected by Northern blot analysis, reverse transcriptase PCR revealed that these genes are also cotranscribed as a single RNA message in early exponential growth. Primer extension analysis revealed the presence of two cidBC transcription start sites, but no apparent σB-dependent promoter consensus sequence was identified in these regions. The rsbU gene was also shown to have a positive impact on murein hydrolase activity but a negligible effect on sensitivity to penicillin-induced killing. These results suggest that the lrgAB and cidBC genes may be part of the S. aureus σB-controlled stress regulon.
UR - http://www.scopus.com/inward/record.url?scp=2342546598&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2342546598&partnerID=8YFLogxK
U2 - 10.1128/JB.186.10.3029-3037.2004
DO - 10.1128/JB.186.10.3029-3037.2004
M3 - Article
C2 - 15126464
AN - SCOPUS:2342546598
SN - 0021-9193
VL - 186
SP - 3029
EP - 3037
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 10
ER -