title: The enhancin-like metalloprotease from the Bacillus cereus group is regulated by the pleiotropic transcriptional activator PlcR but is not essential for larvicidal activity.
abstract: Bacillus cereus group bacteria produce virulence factors. Many of these are regulated by the pleiotropic transcriptional activator PlcR, which is implicated in insect virulence. In silico analysis of the B. cereus strain ATCC14579 genome showed an enhancin-like gene preceded by a typical PlcR binding sequence. The gene is predicted to encode a polypeptide showing 23-25% identity with enhancins from several baculoviruses and 31% with that of Yersinia pestis. Viral enhancin acts after oral infection and degrades the peritrophic matrix of various Lepidopteran larvae. To rule out a possible implication of Bacillus enhancin in insect virulence, we sequenced the enhancin gene from the Bacillus thuringiensis 407-crystal minus strain and investigated its gene regulation and larvicidal activity. A typical metalloprotease zinc-binding domain (HEIAH) was detected and the gene was named mpbE (metalloprotease bacillus enhancin). An mpbE'-lacZ transcriptional fusion demonstrated that mpbE belongs to the PlcR regulon. The mpbE mutant was fed to Galleria mellonella larvae, and no significant reduction in virulence was observed. However, this may not exclude MpbE from a role in pathogenesis.
authors.affiliation: Unité Génétique Microbienne et Environnement, I.N.R.A., La Minière, Guyancourt, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Hajaij-Ellouze
authors.forename: Sinda
authors.initials: S
authors.lastname: Fedhila
authors.forename: Didier
authors.initials: D
authors.lastname: Lereclus
authors.forename: Christina
authors.initials: C
authors.lastname: Nielsen-LeRoux
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001409:Bacillus cereus / Q000201:enzymology* / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology / Q000502:physiology*; D001427:Bacterial Toxins / Q000494:pharmacology; D001483:Base Sequence; D004731:Endotoxins / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D006460:Hemolysin Proteins; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva; D045726:Metalloproteases / Q000235:genetics* / Q000494:pharmacology*; D008969:Molecular Sequence Data; D015534:Trans-Activators / Q000502:physiology*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C099480:PlcR protein, Bacillus; D015534:Trans-Activators; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D045726:Metalloproteases