Transposable Elements and Their Use as Genetic Tools in Arthropods

The aim of the research presented in this thesis is to examine the transposition mechanism of Class 2 transposons and to assess their employment as genetic tools in arthropod genomes. The first chapter reviews transposable genetic elements and their intimate relationship with eukaryotic genome diversity, methods of host genome control for maintaining genome integrity, including the piRNA system, and the current. Chapter two introduces a hAT transposable element, Hermes, that originates from the arthropod genome of Musca domestica. The Hermes element is an active transposon that has been shown to transform several non-homologous arthropod species. Our laboratory has participated in a collaborative research project to understand to molecular details of Hermes transposition by crystal structure and biochemical assays. The research outlined in chapter two provides a rationale for the occurrence of Hermes as an octameric protein with multiple DNA binding domains, as Hermes is the only hAT transposable element for which a co-crystal structure has been successfully produced. Chapter three introduces a newly described MULE element from the genome of mosquito Aedes aegpyti, a major global arboviral vector. The research outlined demonstrates that the Ae. aegypti Muta1 element is active in cell culture and can transform the model dipteran, Drosophila melanogaster, and can remobilize in the germline. Chapter four examines the potential of the Muta1 element as the bases for a novel forward genetics-based tool in the arbovector species, Aedes aegypti, for which no enhancer trap system has been effectively developed. This chapter also outlines potential challenges to implementing a transposon-based tool in this species due to their evolutionarily expanded piRNA pathway. Chapter five explains the ability of the Muta1 element to transform and remobilize in two Anopheles mosquito species, and explores the potential benefit of having a novel enhancer trap system to deploy in mosquito species