Characterization of DNA Repair Function In DNA2 Mutants
Department
Biology
Abstract
DNA damage can cause mutations that lead to cancer and disease in many organisms. Drosophila is an excellent model for studying DNA repair mechanisms because it contains orthologs for many DNA repair genes. An ortholog of the repair and replication gene DNA2 has been recently identified as mus109 in Drosophila. There are three available alleles of Dna2 (Dna2D1, Dna2D2, and Dna2lS) that have been shown to have sensitivity of MMS and ionizing radiation. However the repair function of Dna2 has not yet been fully characterized. To identify the pathways associated with Dna2, we treated combinations of mutant alleles (Dna2D1/Dna2lS and Dna2D2/Dna2lS) with mutagens that stress various replication and repair processes. We found that Dna2 mutant flies were sensitive to hydroxyurea and topotecan, suggesting that Dna2 is important in responding to replication stress. In contrast, Dna2 mutants were not sensitive to potassium bromate (oxidative stress) or bleomycin (radiomimetic, double-strand breaks), suggesting that Dna2 is not critical in those repair processes. We also tested the lifespan of our Dna2 mutants and found that the mutation had little effect on lifespan compared to w1118 wild type controls. We hypothesize that differences in mutagen sensitivity between the Dna2D1 and Dna2D2 alleles can be attributed to differences in mutant protein functionality, as the Dna2D2 mutation occurs downstream of the Dna2D1 mutation, which may allow for more functional protein to be translated. Together these results provide researchers with the fundamental understanding they need to better explore how DNA repair pathways related to aging and disease.
Faculty Sponsor
Elyse Bolterstein, Northeastern Illinois University
Characterization of DNA Repair Function In DNA2 Mutants
DNA damage can cause mutations that lead to cancer and disease in many organisms. Drosophila is an excellent model for studying DNA repair mechanisms because it contains orthologs for many DNA repair genes. An ortholog of the repair and replication gene DNA2 has been recently identified as mus109 in Drosophila. There are three available alleles of Dna2 (Dna2D1, Dna2D2, and Dna2lS) that have been shown to have sensitivity of MMS and ionizing radiation. However the repair function of Dna2 has not yet been fully characterized. To identify the pathways associated with Dna2, we treated combinations of mutant alleles (Dna2D1/Dna2lS and Dna2D2/Dna2lS) with mutagens that stress various replication and repair processes. We found that Dna2 mutant flies were sensitive to hydroxyurea and topotecan, suggesting that Dna2 is important in responding to replication stress. In contrast, Dna2 mutants were not sensitive to potassium bromate (oxidative stress) or bleomycin (radiomimetic, double-strand breaks), suggesting that Dna2 is not critical in those repair processes. We also tested the lifespan of our Dna2 mutants and found that the mutation had little effect on lifespan compared to w1118 wild type controls. We hypothesize that differences in mutagen sensitivity between the Dna2D1 and Dna2D2 alleles can be attributed to differences in mutant protein functionality, as the Dna2D2 mutation occurs downstream of the Dna2D1 mutation, which may allow for more functional protein to be translated. Together these results provide researchers with the fundamental understanding they need to better explore how DNA repair pathways related to aging and disease.