PMID:18790863

Citation	Okumura, K, Ohtani, K, Hayashi, H and Shimizu, T (2008) Characterization of genes regulated directly by the VirR/VirS system in Clostridium perfringens. J. Bacteriol. 190:7719-27
Abstract	Analysis of the complete sequence of the genome of Clostridium perfringens strain 13 resulted in identification of five genes, including pfoA (encoding theta toxin) and vrr (encoding VirR/VirS-regulated RNA), with consensus VirR-binding sequences upstream of the open reading frame (ORF), suggesting that expression of these genes may be regulated directly by the two-component VirR/VirS system. To test this possibility, we examined VirR/VirS system-mediated transcriptional regulation of three genes, virT, ccp (encoding alpha-clostripain), and virU, with the novel VirR-binding sequences. Northern analysis revealed that the steady-state levels (increases or decreases in the amounts of RNA expressed) of virT, ccp, and virU mRNAs were lower in a virR mutant strain than in the wild-type strain, as were the levels of the pfoA and vrr transcripts. The consensus VirR-binding sites were located similarly relative to the transcription start sites in the virT, ccp, and virU promoters. Mutation and overexpression analyses with virT and virU revealed that the virT gene product has a negative effect on expression of pfoA and ccp, whereas the virU gene product positively affects expression of pfoA, virT, ccp, and vrr. Nonsense and frameshift mutations in the virT or virU putative ORF did not affect the regulatory functions, suggesting that virT and virU may encode RNA regulators rather than proteins. These results suggest that a complex regulatory network, perhaps involving several regulatory RNA molecules, governs the expression of the VirR/VirS regulon in C. perfringens.
Links	PubMed PMC2583603 Online version:10.1128/JB.01573-07
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Base Composition; Chromosome Mapping; Chromosomes, Bacterial; Clostridium perfringens/genetics; Clostridium perfringens/metabolism; DNA, Bacterial/genetics; Gene Expression Regulation, Bacterial/physiology; Genome, Bacterial; Mutagenesis, Site-Directed; Mutation; Protein Binding; Regulon
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CLOPF:Q46215		GO:0006355: regulation of transcription, DNA-dependent	ECO:0000315:		P		Figure 3A shows that initiation of transcription at certain DNA initiation sites is dependent on VirR/VirS system.	complete CACAO 3418
CLOPF:Q46215	involved_in	GO:0006355: regulation of transcription, DNA-templated	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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