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The fimbrial gene cluster of Haemophilus influenzae type b
Author(s) -
Ham S. Marieke,
Alphen Loek,
Mool Frits R.,
Putten Jos P. M.
Publication year - 1994
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1994.tb00461.x
Subject(s) - biology , fimbria , operon , gene cluster , gene , bacterial outer membrane , periplasmic space , genetics , pilus , promoter , haemophilus influenzae , microbiology and biotechnology , fimbriae proteins , biogenesis , virulence , mutant , escherichia coli , gene expression , bacteria
Summary Haemophilus infuenzae 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.