RT Journal Article
SR Electronic
T1 RopB represses the transcription of <em>speB</em> in the absence of SIP in group A <em>Streptococcus</em>
JF Life Science Alliance
JO Life Sci. Alliance
FD Life Science Alliance LLC
SP e202201809
DO 10.26508/lsa.202201809
VO 6
IS 6
A1 Chiang-Ni, Chuan
A1 Chen, Yan-Wen
A1 Chen, Kai-Lin
A1 Jiang, Jian-Xian
A1 Shi, Yong-An
A1 Hsu, Chih-Yun
A1 Chen, Yi-Ywan M
A1 Lai, Chih-Ho
A1 Chiu, Cheng-Hsun
YR 2023
UL http://www.life-science-alliance.org/content/6/6/e202201809.abstract
AB RopB is a quorum-sensing regulator that binds to the SpeB-inducing peptide (SIP) under acidic conditions. SIP is known to be degraded by the endopeptidase PepO, whose transcription is repressed by the CovR/CovS two-component regulatory system. Both SIP-bound RopB (RopB-SIP) and SIP-free RopB (apo-RopB) can bind to the speB promoter; however, only RopB-SIP activates speB transcription. In this study, we found that the SpeB expression was higher in the ropB mutant than in the SIP-inactivated (SIP*) mutant. Furthermore, the deletion of ropB in the SIP* mutant derepressed speB expression, suggesting that apo-RopB is a transcriptional repressor of speB. Up-regulation of PepO in the covS mutant degraded SIP, resulting in the down-regulation of speB. We demonstrate that deleting ropB in the covS mutant derepressed the speB expression, suggesting that the speB repression in this mutant was mediated not only by PepO-dependent SIP degradation but also by apo-RopB. These findings reveal a crosstalk between the CovR/CovS and RopB-SIP systems and redefine the role of RopB in regulating speB expression in group A Streptococcus.