Caroline Phan, Thomas Mason, Vivienne Fang’18
Faculty Sponsor: Dr. Karen Hales
Drosophila spermatogenesis is a model system which we use to study mitochondrial morphology. During spermatogenesis mitochondria undergo dramatic shape changes. This delicate balance between fusion and fission is integral to the health of both the mitochondrial network and the cell. In the Z2-3738 mutant line, in which the testis-specific gene CG5755 is mutated, the mitochondria become short and fragmented, implicating CG5755’s role in mitochondrial shaping. SLC25A46, the human ortholog, localizes to the outer mitochondrial membrane and encodes for a protein that interacts with mitofilin, mitofusin, and lipid pathways (Abrams et al., 2018). This study was undertaken to characterize CG5755 by identifying (1) functional connections among CG5755, mitofilin, and mitofusin (fzo) and (2) CG5755 protein localization. We created CG5755- homozygous and mitofilin RNAi knocked-down mutants. These data showed an inconclusive mutant phenotype. We also crossed CG5755- and fzo- mutants. The preliminary data from the mitofusin and CG5755 double mutants suggest that there is a synthetic phenotype. We found small or absent nuclei and misshapen nebenkern, a structure formed when two mitochondrial derivatives wrap around each other. Aside from genetic interactions, we developed a transgenic construct of CG5755 with GFP to visualize the protein product of CG5755. The localization elucidates interactions with other proteins and organelles. We found that CG5755 localizes to the sperm bundles. These data are consistent with the mutant phenotype in the sperm bundles as well. Ultimately, these data ground CG5755’s role in mitochondrial shaping and preface some functional interactions.