2023 1 B1

Determining the Localization of Cell-Fate Determinants in Jagunal-Deficient Mutant Drosophila Embryos

By: Ethan Lew

Department: Biology

Faculty Advisor: Dr. Blake Riggs

Asymmetric cell division (ACD) is fundamental for generating neuronal diversity during development of the Drosophila nervous system. Neuronal stem cells, known as neuroblasts divide asymmetrically to generate self-renewing neuroblasts and a neuronal progenitor cell, a ganglion mother cell (GMC). GMC undergo differentiation to produce neurons and glia cells. Various cell fate determinants regulate ACD in neuroblast cells, including the transcription factor Prospero, a protein that helps regulate the anterior-posterior axis during development. Previously, our laboratory has identified the protein Jagunal, necessary for ACD in the developing Drosophila embryo and the proper partitioning of the endoplasmic reticulum (ER). Jagunal inhibition via RNAi demonstrated a loss of asymmetrical ER partitioning. This result led us to ask if the organelle-associated protein Jagunal aids in the regulation of ACD? We sought out to determine the localization of specific cell fate determinant in a Jagunal-deficient mutant. We used immunocytochemistry to mark specific cell fate determinants during the early stages of Drosophila embryo development. Using stage 10-11 embryos we used antibodies against Prospero to determine their localization within cells undergoing mitosis. For fly strains we used Ore-R stains as our wildtype control and we used JagnQ21X embryos for our Jagunal-null mutant embryos. Our results indicate that in a null mutant, the cell fate determinant Prospero is found to localize as a crescent on the basal membrane of the neuroblast and within the cytoplasm of the GMC in Ore-R embryos. Future studies will involve determining the localization of Jagunal in neuroblast cells to determine colocalization with other cell-fate determinants.