Research Assistant University of South Carolina Aiken Aiken, South Carolina
Body of Abstract: Transposable elements (TEs) are segments of DNA that “jump” to different locations in an organism’s genome. TEs are important because they can cause mutations that result in genetic diversity and facilitate evolution. TEs are also being developed into genome editing tools because they can be inserted into targeted locations. We studied the transposition behavior of mPing, an active TE from rice that is being developed for targeted insertion in plants. This element is mobilized by the ORF1 and Transposase (TPase) proteins of the related Pong element. Our goal was to create hyperactive forms of Pong TPase to increase mPing transposition, potentially improving its genome editing efficiency. We created a sequence alignment of eighteen related TPases and found six phylogenetically conserved positions where Pong TPase did not have the conserved amino acid. We hypothesized that these non-consensus amino acids were reducing Pong TPase’s catalytic efficiency. We synthesized novel clones in which these residues were replaced with the consensus amino acid in the pAG425 overexpression plasmid. Performing yeast transposition assays indicated that five of the six mutations resulted in significantly increased transposition. We are currently combining these mutant versions in hopes of generating a novel Pong TPase protein capable of hyperactive transposition.