Neurochemical Analysis of Drosophila Syndecan Mutants. LaPortia Pierce¹, Marleshia Hall², Olugbenga Doherty², Maria Deluca³, Janis O'Donnell². 1) Department of Natural Sciences, Stillman College, Tuscaloosa, AL; 2) Department of Biological Sciences, University of Alabama, Tuscaloosa, AL; 3) Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL.

   Syndecans are transmembrane proteins that function as co-receptors that regulate signaling pathways with functions as diverse as cell adhesion, neuronal development, and inflammation. While mammals have four syndecan proteins encoded by four different genes, Drosophila have only one functionally conserved syndecan gene. Previous quantitative genetic studies identified Drosophila syndecan as a potential candidate gene affecting variation in fat storage. These studies along with human studies also uncovered a role for syndecans in sleep traits. Since dopamine pathways are reported to regulate sleep and arousal, and high-throughput yeast two-hybrid screens identified Drosophila syndecan as an interactor of tyrosine hydroxylase, the rate-limiting enzyme in dopamine biosynthesis, we hypothesized that mutations in the syndecan gene would result in alterations of the neurochemistry of the Drosophila brain, specifically dopamine, and possibly other monoamines as well. High performance liquid chromatography (HPLC) was used to quantify monoamines in the heads of adult flies in three homozygous syndecan mutant strains relative to wild type controls. These analyses revealed alterations in dopamine pools. Interestingly, serotonin levels also were modified suggesting that syndecan may function in a parallel fashion in serotinergic pathways.