DNA transposition is a process that mediates the movement of genetic information (a mobile DNA element) within a genome. Mobile elements are important for increasing genetic diversity in a population over time, but they also can lead to damage within the genome, and ultimately death. As a result, transposition is a tightly regulated process in which many control mechanisms restrict the frequency of transposition events.;A large body of knowledge exists regarding the control of Tn5 transposition; however, there remain a number of key control mechanisms that are poorly understood. I have generated and analyzed a number of transposase mutants to investigate pre-synaptic complex properties of the transposase with regards to controlling synaptic complex formation. This study revealed that amino acid W450 performs a critical function in repressing synaptic complex formation and may be involved in stabilizing an inhibitory conformation of the transposase monomer. I have also generated and analyzed a separate set of transposase mutants to assess transposition regulation through transposase contacts with both donor DNA and target DNA. This study is the first to generate genetic and biochemical evidence as to the positioning of both donor DNA and target DNA within the synaptic complex. The positioning of these DNA molecules suggests that the synaptic complex possesses a bifunctional DNA binding domain that, at different steps in the transposition process, contributes contacts to both of these DNAs.
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