MSc Exit Seminar
Tuesday, August 7, 2018 at 1:10 pm SW -403, University of Toronto at Scarborough
Chun Hua Wei (Hasenkampf Lab)
The role of HOP2 in Homologous Recombination in Arabidopsis thaliana
The purpose of this study was to investigate the role of HOP2 protein in non-meiotic cells in Arabidopsis. HOP2 is already known to be important to meiotic chromosome pairing and homologous recombination, yet the role of HOP2 outside of meiosis is far from being fully elucidated. My study focused on the mitotic chromosome events with and without the application of radiation. In the absence of radiation, no fragments and chromatin bridges were found in hop2-1 plants, but they did seem to experience a modest chromosome separation delay. When irradiated, both genotypes had significant decreases of mitotic indices and increases of bridges. The decreases in mitotic indices were comparable for the two genotypes, suggesting they accomplish repair at similar rates. Irradiated hop2-1 had significantly more mis-repaired breaks, as determined by the bridges. My findings suggest that HOP2 is also important for the fidelity of the exchange process in non-meiotic HR repair.
MSc Exit Seminar
Tuesday, May 29, 2018 at 2:10pm CCT -3000, University of Toronto at Mississauga
Delara Dadsepah (Levine Lab)
Anatomical and Behavioural Characterization of Dpr-Interacting Protein Beta in Drosophila melanogaster
The mammalian limbic system has many important biological functions. During development, the limbic-system associated membrane protein (LSAMP) plays a crucial role by ensuring proper neuronal connectivity within the system. Similarly, the LSAMP homologue in the Drosophila, the Dpr-interacting protein beta (DIP-β), is believed to assist in neuronal formation during the development of the fly central nervous system. Other data suggests that DIP-β even regulates social interactions. Researchers have only more recently begun investigating DIP-β however, and DIP-β remains to be extensively studied. Thus, the aim of this project was to fully characterize DIP-β expression in the brain and the behaviour of DIP-β mutants, to obtain a better understanding of DIP-β function. DIP-β’s predominant expression in the optic lobes and regions in the central brain, along with changes in behavioural rhythmicity observed in DIP-β mutants, suggests DIP-β may be associated with clock mechanisms.
MSc Exit Seminar
Tuesday, May 29, 2018 at 10:10pm, SW 403- University of Toronto at Scarborough
Peilu Gan (Hasenkampf Lab)
The Role of the Arabidopsis Hop2 Protein in Promoting Homologous Chromosome Interactions and Blocking Nonhomologous Interactions
The Homologous Pairing Protein 2 (Hop2) is important for its role in reciprocal genetic exchange in meiosis. It is thought to operate as a part of the double-strand break (DSB) repair pathway. Recent models give two potential roles for Hop2: it acts to promote interactions between homologous chromosomes, or it acts to block interactions between non-homologous chromosomes. The goal of my study was to see if the Hop2 protein acted to block non-homologous interactions by analyzing its role in haploid plants. Haploid hop2-1 mutants were analyzed by light and fluorescent microscopy and compared with haploid WT plants. Like WT haploids, hop2-1 mutants showed univalents in early meiosis. However, unlike WT haploid plants, hop2-1 haploid mutants showed large amounts of DNA fragmentation and chromosomal bridging in anaphase and metaphase for both Meiosis I and Meiosis II. This suggests that Hop2 acts to block non-homologous interactions.