Disease relevance of hpaA

• Restriction fragment length polymorphism in the adhesin gene hpaA of Helicobacter pylori [1].
• This antibody recognized a 29,000-M(r) protein in Western blots (immunoblots) of cell extracts of H. pylori and Escherichia coli cells expressing the cloned hpaA gene [2].
• Construction of a recombinant attenuated Salmonella typhimurium DNA vaccine carrying Helicobacter pylori hpaA [3].
• In the present study we examined serum samples obtained from 65 C. pylori-infected individuals with gastric ulcers, duodenal ulcers, or both and from 121 asymptomatic volunteers, including 62 who were infected with C. pylori, for immunoglobulin G (IgG) specific for the C. pylori neuramin-lactose-binding hemagglutinin (NLBH) [4].

High impact information on hpaA

• Transcript abundance in vitro (mid-log phase) ranged from about 0.004 (feoB and hpaA) to 20 (ureAB, napA, and cag25) copies/cell [5].
• Agglutination of erythrocytes and adherence to AGS cells by a delta hpaA mutant were no different from those of the parent strain, confirming a recent finding of O'Toole et al [6].
• CONCLUSIONS: RFLP typing of hpaA using Sau3A and HinfI provides an additional tool for comparing the genetic relatedness of H. pylori isolates collected during epidemiological and/or treatment studies [1].
• An isogenic mutant generated by insertional inactivation of hpaA was unaffected in its ability to bind four different human cell lines as well as fixed sections of gastric tissue and had hemagglutination properties identical to those of the wild type [2].
• Determination of the sequence of hpaA from strain CCUG 17874 indicated significant differences from that determined by Evans and coworkers in the above-mentioned study, including extension of the gene into the open reading frame 3 downstream of hpaA to produce a protein with an M(r) of 26,414 [2].

Biological context of hpaA

• RESULTS: In comparison with the reported corresponding sequences, the homologies of nucleotide and putative amino acid sequences of the cloned hpaA gene were from 94.25-97.32 % and 95.38-98.46 %, respectively [7].
• DNA sequence of the amplified hpaA gene was assayed, then cloned into the eukaryotic expression vector pIRES through enzyme digestion and ligation reactions [3].
• The results of PCR were all positive, and PCR-SSCP indicated that there may exist the point mutation in gene hpaA or vacA [8].
• The sensitivity and specificity of the four PCR methods, in comparison to the results obtained from histology and the urease test, are as follows: 80.7% and 76% for the hpaA gene; 100% and 76% for the 16S rRNA gene; 84.6% and 80.0% for the 860-bp DNA fragment; 61.5% and 84.0% for the ureC (glmM) gene, respectively [9].

Anatomical context of hpaA

• In order to elucidate the binding of NLBH to gastric epithelium, a peptide (D-P-K-R-T-I-Q-K-K-S) was synthesized [10].

Associations of hpaA with chemical compounds

• This lysine rich sequence from NLBH was proposed to be the receptor-binding site [10].
• NLBH (neuraminyl lactose binding haemagglutinin) a 32 kDa adhesin located on the surface of H. pylori has been shown to have specific affinity towards NeuAcalpha2,3Galbeta1,4Gluc(3'SL) [10].

Analytical, diagnostic and therapeutic context of hpaA

• Amplification of a 375-bp internal DNA fragment of hpaA by PCR demonstrated the presence of the gene in Hp and in two closely related gastric Helicobacters, H. nemestrinae (Hn) and H. acinonyx (Hx), but not in the more distantly related H. felis (Hf) and H. mustelae (Hm) [11].
• We also showed by reverse transcription-polymerase chain reaction (RT-PCR) that the hpaA gene is co-transcribed with the downstream omp18 gene [12].
• Differences among Helicobacter pylori strains isolated from three different populations and demonstrated by restriction enzyme analysis of an internal fragment of the conserved gene hpaA [13].
• All hpaA segments, obtained from 12 different H pylori strains, were digested by HhaI and HaeIII individually and analyzed by agarose gel electrophoresis [14].
• RESULTS: The 750-base pair hpaA gene fragment was amplified from the genomic DNA and was consistent with the sequence of H pylori hpaA by sequence analysis [3].

References