New virulence-activated and virulence-repressed genes identified by systematic gene inactivation and generation of transcriptional fusions in Bordetella pertussis

Abstract

An in silico scan of the partially completed genome sequence of Bordetella pertussis and analyses of transcriptional fusions generated with a new integrational vector were used to identify new potential virulence genes. The genes encoding a putative siderophore receptor, adhesins, and an autotransporter protein appeared to be regulated in a manner similar to Bordetella virulence genes by the global virulence regulator BvgAS. In contrast, the gene encoding a putative intimin-like protein appeared to be repressed under conditions of virulence.

FIG. 1

Map of pFUS2. (a) Main features of the vector. Gm^R, gentamicin resistance cassette; oriT, RP4 origin of transfer, oriV, ColE1 origin of replication; to, a transcriptional terminator to prevent transcription initiation from vector sequences. (b) Sequence surrounding the multiple cloning site of pFUS2. The portion of the nucleotide sequence corresponding to the 3′ end of groES, the intergenic groES-groEL region, and the 5′ end of groEL is shown in bold. The 3′ end of groES and the 5′ end of groEL have been translated (in bold), as has the beginning of lacZ. SD represents the putative ribosome binding site sequence of groEL. β-Gal, β-galactosidase.