The fimbrial gene cluster of Haemophilus influenzae type b.
Haemophilus influenzae infections are preceded by airway colonization, a process facilitated by fimbriae. Here, we identified the complete fimbrial gene cluster of H. influenzae type b. HifA forms the major subunit. HifB, a periplasmic chaperone, and HifC, an outer membrane usher, are typical assembly genes; their inactivation abolished fimbriae formation. HifD and HifE are putative minor subunits, both participating in fimbriae biogenesis. Inactivation of either one drastically reduced fimbriae expression. HifD represents a novel type of fimbrial subunit with lipoprotein characteristics, pointing to a membrane-associated function of HifD. Transcription of all fimbrial genes is coregulated through two clustered promoters. The flanking of the fimbrial gene cluster by repetitive extragenic palindromic sequences together with a partial duplication of an adjacent unrelated operon indicated that the cluster was once inserted in the H. influenzae genome as a mobile virulence unit.
van Ham
S M
SM
Max-Planck-Institut für Biologie, Abteilung Infektionsbiologie, Tübingen, Germany.
van Alphen
L
L
Mooi
F R
FR
van Putten
J P
JP
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000235:genetics* / Q000648:ultrastructure; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D006193:Haemophilus influenzae / Q000145:classification / Q000235:genetics* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D018832:Molecular Chaperones / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D014158:Transcription, Genetic
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C090992:HifA protein, Haemophilus influenzae; C090993:HifB protein, Haemophilus influenzae; C090994:HifC protein, Haemophilus influenzae; C090011:HifD protein, Haemophilus influenzae; C090010:HifE protein, Haemophilus influenzae; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D036781:Fimbriae Proteins