Title: A DNA knot not like any other - exploring the specificity of HBV’s promoter G4-quadruplex

Archee Panwar1, Dhruvi Patel1, and Vanessa Meier-Stephenson1-3
1Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB;
2Department of Medicine, Division of Infectious Diseases, University of Alberta, Edmonton, AB;
3Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB

Background: G4-quadruplexes (G4Q’s) are structures found in the promoter regions of many genes and play a key role in recruiting transcription factors. In Hepatitis B Virus (HBV), there is a G4Q in the pre-core promoter region that recruits a protein called Sp1. How HBV recruits Sp1 to its G4Q despite other potential targets is not known.

Purpose: To test the function of HBV’s pre-core promoter when replaced with different G4Q’s sourced from the human genome.

Method: Mutant plasmids were created by first deleting HBV’s G4Q, then inserting alternate genomic G4Q’s. Luciferase assays were then performed in HepG2 cells to assess the impact on functioning.

Results: Deletion and insertion plasmids have successfully been created. Luciferase assay data currently reveals considerable variability in the expression levels of the mutants.

Conclusions: The G4Q appears to be essential for promoter activity. Further studies of the insertion mutants are warranted to explore their effects on activity.