Event Title

Characterizing The Role Of Glaikit In Oxidative Stress And Embryonic Development In Drosophila Melanogaster

Location

Lobby in front of Auditorium

Start Date

19-4-2019 11:00 AM

Department

Biology

Description

Our DNA is constantly under attack from environmental toxins, UV radiation and other mutagens. This can cause oxidative stress, which is an overabundance of highly unstable oxygen molecules, or free radicals, resulting in extensive DNA damage and cancer. DNA self-repair mechanisms play a critical role in repairing the damage caused by oxidative stress. Tyrosyl-DNA phosphodiesterase (TDP1) aids in the repair of topoisomerase-mediated double-strand breaks (DSBs) in DNA. In humans, TDP1 mutations lead to spinocerebellar ataxia with axonal neuropathy (SCAN1). SCAN1 patients suffer from reduced sensation and motor abilities, often becoming wheelchair dependent later in life. Our research uses the Drosophila melanogaster homologous gene, glaikit, to further understand how TDP1 aids in the repair of DNA damage caused by oxidative stress. Previous research indicates that gkt mutants (gkt c03958 ) are sensitive to camptothecin and bleomycin, which are chemotherapeutics that cause DSBs. Morphologically, gkt c03958 flies display no outward defects, but published data shows that female mutants have reduced lifespans and motility. We confirmed the gkt c03958 mutation by genotyping using PCR, and demonstrating larval sensitivity to camptothecin. We also observed camptothecin-induced rough eye phenotypes, indicating significant cellular damage during development. Glaikit larvae were not sensitive to paraquat, an herbicide that induces oxidative stress, indicating that glaikit does not play a major role in repairing oxidative damage at the larval stage. Gkt is most highly expressed in the embryonic stages of fly development and in the testes and ovaries of males and females. We sought to determine if fertility was affected in gkt c03958 mutants by conducting hatching frequencies on male, female, and aged male gkt mutants. Fertility in young and aged male gkt c03958 mutants is unaffected; however, fertility in females may be affected as shown by significantly lower hatching frequency in eggs laid by gkt mutants. Glaikit may be involved in embryonic development and the decreased hatching phenotype could be caused by defects in syncytial nuclear division due to an accumulation of DSBs during embryogenesis. Further research will focus on confirmation of mutant phenotypes using alternate gkt mutant alleles, measuring embryo toxicity to DNA damaging reagents, and quantifying anaphase bridges in embryo nuclei to determine if there are defects in syncytial nuclear division.

Comments

Elyse Bolterstein is the faculty sponsor of this poster.

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Apr 19th, 11:00 AM

Characterizing The Role Of Glaikit In Oxidative Stress And Embryonic Development In Drosophila Melanogaster

Lobby in front of Auditorium

Our DNA is constantly under attack from environmental toxins, UV radiation and other mutagens. This can cause oxidative stress, which is an overabundance of highly unstable oxygen molecules, or free radicals, resulting in extensive DNA damage and cancer. DNA self-repair mechanisms play a critical role in repairing the damage caused by oxidative stress. Tyrosyl-DNA phosphodiesterase (TDP1) aids in the repair of topoisomerase-mediated double-strand breaks (DSBs) in DNA. In humans, TDP1 mutations lead to spinocerebellar ataxia with axonal neuropathy (SCAN1). SCAN1 patients suffer from reduced sensation and motor abilities, often becoming wheelchair dependent later in life. Our research uses the Drosophila melanogaster homologous gene, glaikit, to further understand how TDP1 aids in the repair of DNA damage caused by oxidative stress. Previous research indicates that gkt mutants (gkt c03958 ) are sensitive to camptothecin and bleomycin, which are chemotherapeutics that cause DSBs. Morphologically, gkt c03958 flies display no outward defects, but published data shows that female mutants have reduced lifespans and motility. We confirmed the gkt c03958 mutation by genotyping using PCR, and demonstrating larval sensitivity to camptothecin. We also observed camptothecin-induced rough eye phenotypes, indicating significant cellular damage during development. Glaikit larvae were not sensitive to paraquat, an herbicide that induces oxidative stress, indicating that glaikit does not play a major role in repairing oxidative damage at the larval stage. Gkt is most highly expressed in the embryonic stages of fly development and in the testes and ovaries of males and females. We sought to determine if fertility was affected in gkt c03958 mutants by conducting hatching frequencies on male, female, and aged male gkt mutants. Fertility in young and aged male gkt c03958 mutants is unaffected; however, fertility in females may be affected as shown by significantly lower hatching frequency in eggs laid by gkt mutants. Glaikit may be involved in embryonic development and the decreased hatching phenotype could be caused by defects in syncytial nuclear division due to an accumulation of DSBs during embryogenesis. Further research will focus on confirmation of mutant phenotypes using alternate gkt mutant alleles, measuring embryo toxicity to DNA damaging reagents, and quantifying anaphase bridges in embryo nuclei to determine if there are defects in syncytial nuclear division.