Genetic Variation for Dipeptidase-B mRNA Isoforms in Drosophila melanogaster

Mariesa SlaughterSlaughter
Advisor - Kazuo Hiraizumi

Peptidases, found ubiquitously among organisms, play an important role in protein hydrolysis (necessary for many processes, including digestion). The peptidase system in Drosophila melanogaster consists of leucine aminopeptidases and dipeptidases. The gene for dipeptidase-B (DIP-B), one of the three major dipeptidases found in Drosophila, encodes three mRNA isoforms, which differ only in the 5’ untranslated region. Previous studies have indicated greater DIP-B enzyme activity during the adult stage than during the pupal stage of both CL55 and NC25III Drosophila strains and that DIP-B enzyme activity was overall significantly greater in the CL55 strain than the NC25III strain. The exact function of DIP-B is unknown, but analysis of the mRNA isoform expression levels might help to identify the functional role of DIP-B. Differences in mRNA isoform composition and quantities of isoforms between the strains were evaluated to determine possible correlation between DIP-B enzyme activity and transcript levels. The relative quantity of DIP-B isoforms was assessed at the adult and pupal stages using quantitative RT-PCR. Initial findings of this study will be reported.