Mentor:___Dr. Andrea Castillo_____________________________________________________________________________
TRiO McNair Research Internship:____________________________________________________________
Using Saccharomyces cerevisiae to Identify Helicobacter pylori T4SS Effectors (Summer 2014)
Helicobacter pylori is a human gastric pathogen that infects 50% of the world's population. Although many infections are asymptomatic, gastric disease occurs in 10-15% of those infected. The more virulent strains of H. pylori often contain the cytotoxin-associated gene pathogenicity island (cagPAI), which encodes a type IV secretion system (T4SS). The T4SS is used by H. pylori to transfer the CagA protein from the bacterium into human gastric epithelial cells; this transfer results in a variety of cell changes associated with disease. The goal of this study is to identify additional H. pylori proteins that act like CagA. A recent study identified twenty-four potential CagA-like proteins by looking for key C-terminal amino acid residues present in CagA. Our goal is to determine if these potential CagA-like proteins negatively affect eukaryotic cell function. To do this, we have implemented a model yeast system used successfully by others to identify bacterial virulence factors that are naturally transported into eukaryotic cells; in this system we will express the H. pylori putative CagA-like proteins and look for reduced growth of yeast. Thus far, we have tested CagA in this system and found that yeast growth is reduced when CagA is expressed in yeast compared to when our vector alone is expressed in yeast. We have cloned our first putative CagA-like protein, HP0119, into our vector and are poised to test this protein for its ability to confer growth defects on yeast. In our future studies we will test as many of the twenty four CagA-like proteins as possible.
Honors and Awards:______________________________________________________________________
National Honor Society
Presidential Honor Award
Leonard Fowler Scholarship Award
Connie Long Memorial Award
phone: 509.359.6200 (campus operator)
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