A genetic screen to identify novel Helicobacter pylori virulence factors using Saccharomyces cerevisiae as a model eukaryotic cell

Helicobacter pylori is a spiral, gram-negative bacterium that colonizes the stomachs of approximately 50% of the World\u27s population overall and is a major etiological agent of human gastric adenocarcinoma. Of infected individuals, only 10-15% develop severe gastric disease due to environmental factors, host genetic factors, and more significantly, genetic differences in the infecting H pylori strains. Type I strains of H pylori contain a 40-kb cytotoxin-associated pathogenicity island (cag PAl) that encodes and secretes the CagA protein into host epithelial cells via a type IV secretion system. To date, CagA is the only identified effector protein of the cag PAI. The goal of this study was to identify novel H pylori virulence factors, to further elucidate their role in H pylori virulence and their potential as novel effectors of the cag PAI. In the work presented here, we generated an H pylori genomic plasmid library and screened this library in Saccharomyces cerevisiae for toxic effects. We initially identified 2 candidate H pylori virulence factors, however, after further analysis these candidates were not toxic to S. cerevisiae and are no longer genes of interest. To identify novel H pylori virulence factors, others in the lab are addressing pitfalls found in this study to conduct a better-structured screen that we believe will be successful in identifying H pylori genes of interest --Document