Abstract
AbstractThe dopaminergic system has been extensively studied for its role in behavior in various animals as well as human neuropsychiatric and neurological diseases. However, we still know little about how dopamine levels are tightly regulatedin vivo. In order to identify novel regulators of dopamine levels, we utilizedDrosophila melanogastercuticle pigmentation as a readout, where dopamine is used as a precursor to melanin. First, we measured dopamine from classical mutants of genes that are known to be important for cuticle pigmentation to understand the relationship between dopamine levels and cuticle color. We then performed an RNAi-based screen to identify novel regulators of cuticle pigmentation. We identified 153 genes that were not only enriched for conserved homologs and disease-associated genes, but were unexpectedly enriched for multiple developmental signaling pathways and mitochondria-associated proteins. Upon measuring dopamine from 35 prioritized candidates from this cohort, we found 10 that caused significant reduction in dopamine in the head while one caused an increase. While most of these 11 genes are expressed in the fly brain, only two of them,cluandmask,altered dopamine levels specifically in the brain upon knockdown in dopaminergic cells. Interestingly,maskmay act as a hub of dopamine regulation since it is associated with three nodes found in our screen (Receptor tyrosine kinase/EGF signaling, Hippo signaling, and mitochondrial dynamics). Further examination suggests that Mask likely acts on dopamine synthesis by regulating transcription of the rate-limiting dopamine synthesis enzyme,tyrosine hydroxylase. In conclusion, this screen identified 11 new regulators of dopamine levels and provides molecular handles to investigate how dopamine levels are controlledin vivo, as well as revealed an unexpected relationship between fly pigmentation genes, developmental signaling and human neurological and neurodevelopmental disease genes.
Publisher
Cold Spring Harbor Laboratory