Identification and characterization of a DNA region involved in the export of capsular polysaccharide by Actinobacillus pleuropneumoniae serotype 5a

Actinobacillus pleuropneumoniae synthesizes a serotype-specific capsular polysaccharide that acts as a protective barrier to phagocytosis and complement-mediated killing. To begin understanding the role of A. pleuropneumoniae capsule in virulence, we sought to identify the genes involved in capsular...

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Bibliographic Details
Published in:Infection and Immunity 1997-06, Vol.65 (6), p.2491-2496
Main Authors: Ward, C.K. (University of Texas Southwestern Medical Center, Dallas, TX.), Inzana, T.J
Format: Article
Language:English
Subjects:
ACTINOBACILLUS PLEUROPNEUMONIAE
Actinobacillus pleuropneumoniae - genetics
Actinobacillus pleuropneumoniae - physiology
ADN
Bacterial Capsules - physiology
Bacteriology
Base Sequence
Biological and medical sciences
DNA Transposable Elements
DNA, Bacterial - analysis
DNA, Bacterial - chemistry
Fundamental and applied biological sciences. Psychology
Genetic Complementation Test
Genetics
IDENTIFICACION
IDENTIFICATION
Microbiology
Molecular Sequence Data
Nucleic Acid Hybridization
POLISACARIDOS
POLYHOLOSIDE
Polysaccharides, Bacterial - metabolism
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Summary:Actinobacillus pleuropneumoniae synthesizes a serotype-specific capsular polysaccharide that acts as a protective barrier to phagocytosis and complement-mediated killing. To begin understanding the role of A. pleuropneumoniae capsule in virulence, we sought to identify the genes involved in capsular polysaccharide export and biosynthesis. A 5.3-kb XbaI fragment of A. pleuropneumoniae serotype 5a J45 genomic DNA that hybridized with DNA probes specific for the Haemophilus influenzae type b cap export region was cloned and sequenced. This A. pleuropneumoniae DNA fragment encoded four open reading frames, designated cpxDCBA. The nucleotide and predicted amino acid sequences of cpxDCBA contained a high degree of homology to the capsule export genes of H. influenzae type b bexDCBA, Neisseria meningitidis group B ctrABCD, and, to a lesser extent, Escherichia coli K1 and K5 kpsE and kpsMT. When present in trans, the cpxDCBA gene cluster complemented kpsM::TnphoA or kpsT::TnphoA mutations, determined by enzyme immunoassay and by restored sensitivity to a KS-specific bacteriophage. A cpxCB probe hybridized to genomic DNA from all A. pleuropneumoniae serotypes tested, indicating that this DNA was conserved among serotypes. These data suggest that A. pleuropneumoniae produces a group II family capsule similar to those of related mucosal pathogens
ISSN:0019-9567
1098-5522
DOI:10.1128/IAI.65.6.2491-2496.1997