Allelic Variation within Helicobacter pylori babA and babB
AUTOR(ES)
Pride, David T.
FONTE
American Society for Microbiology
RESUMO
Helicobacter pylori strains show both geographic and disease-associated allelic variation. We investigated the diversity present in two genes, babA and babB, which are members of a paralogous family of outer membrane proteins. Eleven family members within a single H. pylori strain, predicted to encode proteins with substantial N- and C-terminal similarity to each other, were classified as babA paralogues. In their central regions, most are less than 54% related to one another. Examining the babA and babB central regions in 42 H. pylori strains from different geographic locales, we identified five different allele groups of babA (AD1 to AD5) and three different allele groups of babB (BD1 to BD3). Phylogenetic analysis revealed that the allelic groupings of babA and babB are independent of one another and that, for both, geographic variation is present. Analysis of synonymous and nonsynonymous substitutions in these regions showed that babA is more diverse, implying an earlier origin than that of the same region of babB, but that the babA diversity region may have more functional constraints. Although recombination has been central to the evolution of both genes, with babA and babB showing low mean compatibility scores and homoplasy ratios of 0.71 and 0.67, respectively, recombination is not sufficient to obscure evidence of clonal descent. Despite the involvement of babA in binding to the host blood group antigen Lewis B, neither the presence of different babA allele groups nor that of different babB allele groups is a determining factor in Lewis B binding of H. pylori strains.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=97998Documentos Relacionados
- Heterogeneity among Helicobacter pylori Strains in Expression of the Outer Membrane Protein BabA
- High Prevalence of cagA- and babA2-Positive Helicobacter pylori Clinical Isolates in Taiwan
- Clinical Relevance of the babA2 Genotype of Helicobacter pylori in Japanese Clinical Isolates
- babA2- and cagA-Positive Helicobacter pylori Strains Are Associated with Duodenal Ulcer and Gastric Carcinoma in Brazil
- Metastability of Helicobacter pylori bab adhesin genes and dynamics in Lewis b antigen binding