By Andrea Waltrip, Delaney Baratka, Shyanne Michael

Faculty Mentor: Ginny Morriss

Abstract

Myotonic Dystrophy Type 1, DM1, is a multi-systemic disorder that results from expression of expanded CTG repeats in the DMPK gene in humans. Three transgenic Drosophila melanogaster lines have been created containing 60, 250, or 480 CTG repeats to model DM1. The transgenic repeats are expressed using the GAL4/UAS system. Expression of long-repeat transgenes ((CTG)250 and i(CTG)480) produces phenotypes consistent with DM1, relative to control lines ((CTG)60). The precise chromosomal location of insertion of the transgenes has not been reported. We used classical genetic approaches to localize CTG-repeat transgene insertion to a specific chromosome. We used GAL4 drivers on different chromosomes to drive expression of repeats and assessed phenotypic ratios of eye color, climbing capability, and flight ability, which is affected in DM1 flies. Results from the genetic analysis suggest that the (CTG)250 and i(CTG)480 transgene are likely localized to chromosome 2 and the (CTG)60 transgene is likely localized to chromosome 3. Knowing the location of the transgenes can allow for more practical mating schemes to study DM1 disease mechanisms, as well as provides crucial information for understanding transgene expression.