We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Identification and characterization of a cell envelope protein of Haemophilus influenzae contributing to phase variation in colony opacity and nasopharyngeal colonization.
- Authors
Weiser, Jeffrey N.; Chong, Suzanne T.H.; Greenberg, Danielle; Fong, Winifred
- Abstract
<em>Haemophilus influenzae</em> undergoes spontaneous phase variation in colony morphology. Organisms from transparent colonies efficiently colonize the nasopharynx in an infant rat model of <em>H. influenzae</em> carriage, whereas organisms from more opaque colonies are deficient at colonization. A genetic approach relying on the transformability of <em>H. influenzae</em> was used to identify a locus contributing to opacity variation. By screening a library of chomosomal DNA from an opaque variant of strain Rd, it was possible to isolate a single clone capable of transforming a transparent Rd host to a more opaque phenotype. A region containing two genes, designated <em>oapA</em> and <em>oapB</em>, was identified. The deduced amino acid sequence of <em>oapB</em> has similarity to a consensus sequence for bacterial lipoproteins. Genetically defined mutations in <em>oapA</em> were transformed into the transparent Rd to confirm that this gene is required for expression of the transparent colony phenotype. Although <em>oapA</em> lacks a signal sequence, gene fusions to <em>phoA</em> show that <em>OapA</em> is secreted in <em>H. infiuenzae</em> and undergoes phase variation in expression. Mutagenesis of <em>oapA</em> in strain Rd, and type b strain Eagan, resulted in loss of the ability to colonize the nasopharynx of infant rats. The type b mutant, however, was as virulent as its parent strain when inoculated irtraperitoneally. This suggests that the contribution of OapA to pathogenesis is limited to events associated with colonization of the mucosal surface.
- Subjects
HAEMOPHILUS influenzae; NASOPHARYNX; DNA replication; PASTEURELLACEAE; THROAT
- Publication
Molecular Microbiology, 1995, Vol 17, Issue 3, p555
- ISSN
0950-382X
- Publication type
Article
- DOI
10.1111/j.1365-2958.1995.mmi_17030555.x