Author(s): Kylie DeNiro
Mentor(s): Sophie Caron, Andrew Butts
Institution U of U
The mammalian activity-regulated cytoskeleton-associated protein (ARC) gene is expressed in neurons and is known to regulate different neuronal processes, such as memory formation and sleep homeostasis. In Drosophila melanogaster, the functions of the homologs dArc1 and dArc2 – which are also expressed in neurons of the fly brain – remain largely unknown. To begin investigating the role of dArc genes in flies, our lab generated novel dArc mutants in which both dArc genes were deleted, referred to as the dArc1/2-/- mutant. In these flies, we observe dysregulation of both memory and sleep behaviors. To study sleep, we used the Drosophila Activity Monitoring System, which records sleep and activity measurements from individual flies. Our results show that dArc1/2-/- mutant flies show a robust increase in daily sleep compared to wild-type flies. To determine the necessity of dArc genes in sleep, we generated genomic rescues, in which the dArc1/2 genes were reinserted onto the third chromosome, referred to as dArc1/2-/-; dArc1/2GR. The sleep behavior of the genomic rescue flies is rescued to wild-type levels, suggesting that these dArc genes are necessary for sleep. Next, to identify which neurons express dArc1, we use immunohistochemistry, a technique that utilizes antibodies to bind to specific proteins, to visualize the location of dArc1 proteins in the brain. Our data has shown that dArc1 is expressed in a subset of serotonin neurons. Knockdown of dArc1 in these neurons increases sleep behavior, suggesting that dArc1 in these serotonin neurons is necessary for sleep behavior. There are still many dArc1-expressing neurons that have not been characterized. We plan to use two-photon microscopy to label neuronal anatomy and compare them to the Drosophila connectome to identify and characterize the remaining neurons that express dArc1.