Identification of a novel locus that regulates expression of toxin genes in<i>Clostridium perfringens</i>

Ohtani, Kaori; Bhowmik, Sushanta K.; Hayashi, Hideo; Shimizu, Tohru

doi:10.1111/j.1574-6968.2002.tb11118.x

Cited by 30 publications

(14 citation statements)

References 21 publications

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“…The response regulator VirR directly regulates the expression of pfoA and of three non-coding RNAs, the VR-RNA, VirU and VirT, which in turns control the expression of plc and colA [24-26]. Another small non-coding RNA, VirX regulates pfoA , plc and colA expression independently from the VirS/VirR system [27]. Interestingly, the expression of the ubiGmccBAluxS operon of C. perfringens is repressed by the two-component system VirS/VirR via the VR-RNA [26,28,29].…”

Section: Introductionmentioning

confidence: 99%

Global regulation of gene expression in response to cysteine availability in Clostridium perfringens

et al. 2010

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BackgroundCysteine has a crucial role in cellular physiology and its synthesis is tightly controlled due to its reactivity. However, little is known about the sulfur metabolism and its regulation in clostridia compared with other firmicutes. In Clostridium perfringens, the two-component system, VirR/VirS, controls the expression of the ubiG operon involved in methionine to cysteine conversion in addition to the expression of several toxin genes. The existence of links between the C. perfringens virulence regulon and sulfur metabolism prompted us to analyze this metabolism in more detail.ResultsWe first performed a tentative reconstruction of sulfur metabolism in C. perfringens and correlated these data with the growth of strain 13 in the presence of various sulfur sources. Surprisingly, C. perfringens can convert cysteine to methionine by an atypical still uncharacterized pathway. We further compared the expression profiles of strain 13 after growth in the presence of cystine or homocysteine that corresponds to conditions of cysteine depletion. Among the 177 genes differentially expressed, we found genes involved in sulfur metabolism and controlled by premature termination of transcription via a cysteine specific T-box system (cysK-cysE, cysP1 and cysP2) or an S-box riboswitch (metK and metT). We also showed that the ubiG operon was submitted to a triple regulation by cysteine availability via a T-box system, by the VirR/VirS system via the VR-RNA and by the VirX regulatory RNA.In addition, we found that expression of pfoA (theta-toxin), nagL (one of the five genes encoding hyaluronidases) and genes involved in the maintenance of cell redox status was differentially expressed in response to cysteine availability. Finally, we showed that the expression of genes involved in [Fe-S] clusters biogenesis and of the ldh gene encoding the lactate dehydrogenase was induced during cysteine limitation.ConclusionSeveral key functions for the cellular physiology of this anaerobic bacterium were controlled in response to cysteine availability. While most of the genes involved in sulfur metabolism are regulated by premature termination of transcription, other still uncharacterized mechanisms of regulation participated in the induction of gene expression during cysteine starvation.

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Section: Introductionmentioning

confidence: 99%

Global regulation of gene expression in response to cysteine availability in Clostridium perfringens

et al. 2010

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“…Clostridium are noted to contain either single or multiple QSS, such as: (1) LuxS, (2) Agr, (3) Agr2 that are regulated by peptide signals e.g., AIP ( Table 1) [24][25][26][27][28][29]. Table 1) [30][31][32][33][34].…”

Section: Clostridiummentioning

confidence: 99%

Potential Emergence of Multi-quorum Sensing Inhibitor Resistant (MQSIR) Bacteria

et al. 2015

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Expression of certain bacterial genes only at a high bacterial cell density is termed as quorum-sensing (QS). Here bacteria use signaling molecules to communicate among themselves. QS mediated genes are generally involved in the expression of phenotypes such as bioluminescence, biofilm formation, competence, nodulation, and virulence. QS systems (QSS) vary from a single in Vibrio spp. to multiple in Pseudomonas and Sinorhizobium species. The complexity of QSS is further enhanced by the multiplicity of signals: (1) peptides, (2) acyl-homoserine lactones, (3) diketopiperazines. To counteract this pathogenic behaviour, a wide range of bioactive molecules acting as QS inhibitors (QSIs) have been elucidated. Unlike antibiotics, QSIs don't kill bacteria and act at much lower concentration than those of antibiotics. Bacterial ability to evolve resistance against multiple drugs has cautioned researchers to develop QSIs which may not generate undue pressure on bacteria to develop resistance against them. In this paper, we have discussed the implications of the diversity and multiplicity of QSS, in acting as an arsenal to withstand attack from QSIs and may use these as reservoirs to develop multi-QSI resistance.

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“…The function of the small ORF encoded on VR is still unclear. In 2013, another sRNA, VirX, which had been shown before 65 to regulate pfoA, plc , and colA mRNAs independent of the VirR/VirS system has been found to repress genes encoding positive sporulation regulators like Spo0A and sigma factors E, F, and K 66 . Inactivation of virX led to higher levels of sporulation and enterotoxin production.…”

Section: Srnas From Clostridiummentioning

confidence: 98%

Small regulatory RNAs from low-GC Gram-positive bacteria

Brantl

Brückner

2014

RNA Biology

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Small regulatory RNAs (sRNAs) that act by base-pairing were first discovered in so-called accessory DNA elements—plasmids, phages, and transposons—where they control replication, maintenance, and transposition. Since 2001, a huge body of work has been performed to predict and identify sRNAs in a multitude of bacterial genomes. The majority of chromosome-encoded sRNAs have been investigated in E. coli and other Gram-negative bacteria. However, during the past five years an increasing number of sRNAs were found in Gram-positive bacteria. Here, we outline our current knowledge on chromosome-encoded sRNAs from low-GC Gram-positive species that act by base-pairing, i.e., an antisense mechanism. We will focus on sRNAs with known targets and defined regulatory mechanisms with special emphasis on Bacillus subtilis.

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Identification of a novel locus that regulates expression of toxin genes inClostridium perfringens

Cited by 30 publications

References 21 publications

Global regulation of gene expression in response to cysteine availability in Clostridium perfringens

Global regulation of gene expression in response to cysteine availability in Clostridium perfringens

Potential Emergence of Multi-quorum Sensing Inhibitor Resistant (MQSIR) Bacteria

Small regulatory RNAs from low-GC Gram-positive bacteria

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