The Function of Microtubule Polarity in Drosophila Dendrites

Open Access
Author:
Parmar, Manpreet Kaur
Area of Honors:
Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Melissa Rolls, Thesis Supervisor
  • Stephen Wade Schaeffer, Honors Advisor
  • Dr Gong Chen, Faculty Reader
Keywords:
  • Microtubule Polarity
  • Dendrites
  • Drosophila melanogaster
  • Minus-end-out microtubule
  • Plus-end-out microtubule
  • polarized trafficking
  • Kap3RNAi
  • Rtnl2RNAi
  • Class I neuron
  • ddaE
  • morphology
  • endosomes
  • mitochondria
Abstract:
The nervous system is composed of billions of neurons that communicate rapidly via electrical and chemical signaling to receive, transmit, and integrate information flow throughout the body. Within each neuron, microtubules serve as tracks for long-range transport that is essential for maintaining the cell’s function and survival. The purpose of this research project was to understand how polarity of dendrite microtubules contributes to polarized trafficking of proteins and organelles in a neuron. Since Drosophila melanogaster share many neuronal properties with vertebrates, these fruit flies served as a useful model system for studying neuronal cell biology. Three assays were completed to determine the effect of altering the minus-end-out microtubule orientation of ddaE dendrites to evenly mixed. In all cases, Kap3RNAi was utilized to create an experimental group consisting of larvae with an evenly mixed microtubule orientation, and rtnl2RNAi was used to establish a control group of larvae with predominately minus-end-out microtubules in their dendrites. The class I neuron was imaged with confocal microscopy and analyzed using Image J. Results showed that altering microtubule polarity did not change dendrite morphology significantly but did affect aspects of endosome movement and mitochondrial distribution strongly. A deeper understanding of the contribution of microtubule polarity to polarized trafficking of organelles in the dendrites may aid in advancing research about the structural and functional specialization of dendrites as well as medical therapies for neurodegenerative diseases.