RT Journal Article SR Electronic(1) A1 Jacob-Dubuisson, Françoise A1 Kehoe, Bettina A1 Willery, Eve A1 Reveneau, Nathalie A1 Locht, Camille A1 Relman, David A. YR 2000 T1 Molecular characterization of Bordetella bronchiseptica filamentous haemagglutinin and its secretion machineryThe GenBank accession numbers for the sequences reported in this paper are AF111794, AF111796, AF111797 and AF111798. JF Microbiology, VO 146 IS 5 SP 1211 OP 1221 DO https://doi.org/10.1099/00221287-146-5-1211 PB Microbiology Society, SN 1465-2080, AB Two closely related pathogens, Bordetella pertussis and Bordetella bronchiseptica, share a number of virulence factors. Filamentous haemagglutinin (FHA) is widely regarded as the dominant adhesin of B. pertussis, and its multiple binding activities have been well characterized. This large protein is produced and secreted at high levels by B. pertussis and significantly lower levels by B. bronchiseptica strains. FHA secretion is mediated by a single outer-membrane accessory protein, FhaC. The genes encoding FHA and FhaC in B. bronchiseptica were characterized by sequencing and functional analyses and are highly similar to those of B. pertussis. The most distinctive feature of B. bronchiseptica FHA is additional repeats in the N-terminal portion of the predicted protein. Interestingly, a point mutation in the fhaB promoter region of the B. bronchiseptica GP1 isolate, relative to other isolates, was found to be detrimental to promoter activity and to FHA production. FhaC and the N-terminal secretion domain of FHA of B. bronchiseptica were fully functional for secretion in B. pertussis. Thus, the different levels of FHA secretion by these Bordetella species might reflect differences in physiology, composition and structure of cell envelope, or differential protein degradation. Characterization of FHA expression and function may provide clues as to the basis of host species tropism, tissue localization and receptor recognition., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-146-5-1211