title: High-level genetic diversity in the vapD chromosomal region of Helicobacter pylori.
abstract: Helicobacter pylori isolates from different patients are characterized by diversity in the nucleotide sequences of individual genes, variation in genome size, and variation in gene order. Genetic diversity is particularly striking in vacuolating cytotoxin (vacA) alleles. In this study, five open reading frames (ORFs) were identified within a 4.2-kb region downstream from vacA in H. pylori 60190. One of these ORFs was closely related to the virulence-associated protein D (vapD) gene of Dichelobacter nodosus (64.9% nucleotide identity). A probe derived from vapD of H. pylori 60190 hybridized with only 19 (61.3%) of 31 H. pylori strains tested. Sequence analysis of the vapD region in vapD-negative H. pylori strains revealed that there were two different families of approximately 0.5-kb DNA segments, which were both unrelated to vapD. The presence of vapD was not associated with any specific family of vacA alleles. These findings are consistent with a recombinational population structure for H. pylori.
authors.affiliation: Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2605, USA.
authors.forename: P
authors.initials: P
authors.lastname: Cao
authors.forename: T L
authors.initials: TL
authors.lastname: Cover
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D016384:Consensus Sequence; D005798:Genes, Bacterial; D014644:Genetic Variation; D016680:Genome, Bacterial; D005838:Genotype; D016480:Helicobacter pylori / Q000235:genetics*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C077520:VapD protein, Bacteria