Uncharacterized ORF HUR1 influences the efficiency of non-homologous end-joining repair in Saccharomyces cerevisiae

Non-Homologous End Joining (NHEJ) is a highly conserved pathway that repairs Double-Strand Breaks (DSBs) within DNA. Here we show that the deletion of yeast uncharacterized ORF HUR1, Hydroxyurea Resistancel affects the efficiency of NHEJ. Our findings are supported by Protein-Protein Interaction (PPI), genetic interaction and drug sensitivity analyses. To assess the activity of HURL in DSB repair, we deleted its non-overlapping region with PMR1, referred to as HURL A. We observed that similar to deletion of TPK1 and NEJ1, and unlike YKU70 (important for NHEJ of DNA with overhang and not blunt end), deletion of HUR1-A reduced the efficiency of NHEJ in both overhang and blunt end plasmid repair assays. Similarly, a chromosomal repair assay showed a reduction for repair efficiency when HUR1-A was deleted. In agreement with a functional connection for Hurlp with Tpklp and NEJ1p, double mutant strains Delta hur1-A/Delta tpk1, and Delta hurl-A/Delta nejl showed the samereduction in the efficiency of plasmid repair, compared to both single deletion strains. Also, using a Homologous Recombination (HR) specific plasmid-based DSB repair assay we observed that deletion of HUR1-A influenced the efficiency of HR repair, suggesting that HURL might also play additional roles in other DNA repair pathways.