title: Two different families of hopQ alleles in Helicobacter pylori.
abstract: Helicobacter pylori genomes contain about 30 different hop genes, which encode outer membrane proteins. In this study, we analyzed genetic diversity in the H. pylori hopQ (omp27) locus, which corresponds to HP1177 in the genome of H. pylori reference strain 26,695. hopQ and its flanking genes were PCR amplified from multiple H. pylori strains, and the nucleotide sequences were determined. This analysis revealed the existence of two different families of hopQ alleles. Type I hopQ alleles are present in the genomes of two fully sequenced H. pylori strains, whereas the existence of type II hopQ alleles has not previously been recognized. Type I and type II hopQ alleles are 75 to 80% identical in nucleotide sequences and encode predicted outer membrane proteins that are 68 to 72% identical in amino acid sequences. PCR-based methods were developed to enable rapid differentiation between type I and type II hopQ alleles. Type I hopQ alleles were found significantly more commonly in cag(+)/type s1-vacA strains from patients with peptic ulcer disease than in cag-negative/s2-vacA strains from patients without ulcer disease (P < 0.001). Determination of hopQ allelic types provides a new method for classification of H. pylori strains. Further studies in multiple populations of patients are indicated to evaluate the usefulness of this approach for distinguishing potentially ulcerogenic H. pylori strains from less virulent strains.
authors.affiliation: Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Cao
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Cover
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D015373:Bacterial Typing Techniques; D014644:Genetic Variation; D005838:Genotype; D016480:Helicobacter pylori / Q000145:classification* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001425:Bacterial Outer Membrane Proteins