IDENTIFICATION OF BTR-REGULATED GENES USING A TITRATION ASSAY - SEARCH FOR A ROLE FOR THIS TRANSCRIPTIONAL REGULATOR IN THE GROWTH AND VIRULENCE OF BORDETELLA-PERTUSSIS

Bordetella pertussis is the causative agent of the respiratory disease pertussis or whooping cough. Btr, an oxygen-responsive transcriptiona l regulator of B. pertussis, is homologous to the FNR protein of E. co il. Using a murine respiratory model, we observed in the present study that Btr is important in growth and survival of B. pertussis in vivo. A titration assay was developed that identified genes containing Btr binding sites including B. pertussis sodB and btr, E. coli aspA and a new B. pertussis gene, brg1. The brg1 gene encodes a protein similar t o the LysR family of transcriptional regulators, and its expression is activated threefold by Btr under anaerobic growth conditions but unaf fected by Btr aerobically. The nucleotide sequence flanking bl gl enco des proteins with similarity to various metabolic enzymes. Putative ov erlapping promoters and a Btr binding site (FNR box) were identified i n the DNA sequence between brg1 and the adjacent genes. These interven ing sequences may represent sites for regulation by Btr and Brg1. (C) 1998 Elsevier Science B.V.