Does Wlds protect in Drosophila?

Shaibah, Hassan S (2007) Does Wlds protect in Drosophila? University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Wld^s is a chimeric protein first discovered in the Wld^s mutant mouse. Mice expressing the Wld^s protein exhibit delayed axon degeneration in several injury models including physical, toxin treatment, and disease. In this project I sought to create a system to analyze neurodegeneration in Drosophila and to test if Wld^s protein function is conserved in Drosophila. This was done using both an acute injury and a chronic disease model. The acute injury model was created using the giant fiber (GF) neuron and crushing the GF axon in the cervical connective. In response to this injury wild type GF axons underwent rapid degeneration and were completely cleared within 48 hours of injury. When GF neurons expressing Wld^s were subject to identical injury the severed axons remained intact up to 48 hours post injury. This work confirmed that Wld^s protects axons against injury in Drosophila. Despite this success, the GF axon model was not ideal and did not offer consistent injury. Consequently a second injury model was developed. For this I used a laser to create a focal injury of larval motor axons. In this system wild type injured axons and its neuromuscular junctions (NMJs) degenerated completely within 48 ours of injury. In Wld^s expressing motor neurons injured axons and NMJs did not show any signs of large scale degeneration or clearance within the same time period. Immunohistochemical analysis showed that in wild type larvae the microtubule cytoskeleton is lost within 6 hours of injury, where as in Wld^s expressing larvae the cytoskeleton remained intact even at 48 hours post injury. Thus showing that Wld^s expression can protect the cytoskeleton.