Distribution of Open Reading Frames of Plasticity Region of Strain J99 in Helicobacter pylori Strains Isolated from Gastric Carcinoma and Gastritis Patients in Costa Rica

Abstract

The plasticity region of Helicobacter pylori strain J99 is a large chromosomal segment containing 33 strain-specific open reading frames (ORFs) with characteristics of a pathogenicity island. To study the diversity of the plasticity region, 22 probes corresponding to 20 ORFs inside the plasticity region and two ORFs on its boundaries were hybridized to genomic DNA isolated from clinical strains of H. pylori from patients with gastritis or gastric adenocarcinoma. Highly variable hybridization patterns were observed. The majority of the clinical strains presented a hybridization profile similar to that of J99; thus, these ORFs are not J99 strain specific. No association was found between a particular hybridization pattern and the clinical origin of the strain. Nevertheless, two single ORFs (JHP940 and JHP947) were more likely to be found in gastric cancer strains. They may be new pathogenicity markers. An in vitro expression study of these ORFs was also performed for the J99 strain, under different conditions. Thirteen ORFs were consistently expressed, six were consistently shut off, and three were expressed differentially. Most of the constitutionally expressed genes were located on the 3 part of the plasticity region. Our results show that the plasticity region, rather than being considered a pathogenicity island per se, should be considered a genomic island, which represents a large fragment of foreign DNA integrated into the genome and not necessarily implicated in the pathogenic capacity of the strain.

Helicobacter pylori proinflammatory protein up-regulates NF-κB as a cell-translocating Ser/Thr kinase

“…jhp940 is one of the virulence genes located in the plasticity region of H. pylori J99 (12)(13)(14). An initial systematic study showed increased prevalence of the jhp940 gene in H. pylori from gastric cancer patients (12). An in vivo study showed that JHP940 is strongly expressed in response to the interaction of H. pylori with the gerbil gastric mucosa (15,16).…”

“…Because little is known about many of the genes in the plasticity regions, further studies are necessary to elucidate the roles of genes in these regions in H. pylori-associated pathogenesis. jhp940 is one of the virulence genes located in the plasticity region of H. pylori J99 (12)(13)(14). An initial systematic study showed increased prevalence of the jhp940 gene in H. pylori from gastric cancer patients (12).…”

Duodenal ulcer promoting gene of Helicobacter pylori

“…20 -23 For example, Occhialini et al found that the jhp0940 and jhp0947 genes in the plasticity region were more likely to be found in H pylori from gastric cancer patients from a small group of 17 gastric cancer and 26 gastritis patients from Costa Rica. 20 A follow-up to test the hypothetical relationship was done in 200 strains of H pylori from Brazil, including stains from DU, gastric cancer, and H pylori gastritis patients. The original hypothesis was not confirmed, but the new study suggested a relation between jhp0947 (not jhp0940) and both DU and gastric cancer.…”

Pathogen Evolution In Vivo: Genome Dynamics of Two Isolates Obtained 9 Years Apart from a Duodenal Ulcer Patient Infected with a Single Helicobacter pylori Strain

“…The (cag PAI) rearrangement profiles and cagA-glr motif types were also compared to existing records in the genoBASE pylori database. The presence or absence of the plasticity region open reading frames (ORFs) JHP947, HP986, JHP912, JHP926, JHP931, JHP933, JHP944, and JHP945 was detected based on PCR amplifications employing target sequences and reaction parameters as described by Occhialini et al (20). Purified DNA preparations from the two isolates were used for PCR and sequencing of genes such as glmM (ureC), babB, and oipA as described previously (10).…”