title: Identification of hifD and hifE in the pilus gene cluster of Haemophilus influenzae type b strain Eagan.
abstract: Haemophilus influenzae produces surface structures called pili that promote adherence to human cells. Three genes encoding the major pilus structural component (pilin), chaperone, and usher proteins (designated hifA, -B, and -C, respectively) have been identified previously. In this study, transposon mutagenesis and DNA sequence analysis identified two open reading frames (ORFs) downstream of, and in the same orientation as, hifC. These genes have been designated hifD and hifE. Both genes have predicted C-terminal amino acid homology to HifA, and mutations in either gene resulted in the loss of morphologic and functional pili, indicating that hifD and hifE encode pilus structural components and are required for pilus expression. Another ORF, identified immediately downstream of hifE, has a predicted amino acid sequence that is 70% identical to an aminopeptidase of Escherichia coli called PepN, and a mutation within this ORF did not alter pilus expression. These data indicate that the pepN homolog is not required for pilus biogenesis and that one end of the pilus gene cluster has been defined.
authors.affiliation: Department of Epidemiology, University of Michigan, Ann Arbor 48109.
authors.forename: K W
authors.initials: KW
authors.lastname: McCrea
authors.forename: W J
authors.initials: WJ
authors.lastname: Watson
authors.forename: J R
authors.initials: JR
authors.lastname: Gilsdorf
authors.forename: C F
authors.initials: CF
authors.lastname: Marrs
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000648:ultrastructure*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006193:Haemophilus influenzae / Q000235:genetics* / Q000648:ultrastructure; D018832:Molecular Chaperones / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D009876:Operon; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C090011:HifD protein, Haemophilus influenzae; C090010:HifE protein, Haemophilus influenzae; D018832:Molecular Chaperones; D036781:Fimbriae Proteins