GαolfRegulates Biochemical Signaling in Neurons Associated with Movement Control and Initiation

Abstract

AbstractThe heterotrimeric G-protein α subunit, Gαolf, acts to transduce extracellular signals through G-protein coupled receptors (GPCRs) and stimulates adenylyl cyclase mediated production of the second messenger cyclic adenosine monophosphate. Numerous mutations in theGNALgene, which encodes Gαolf, have been identified as causative for an adult-onset dystonia. These mutations disrupt GPCR signaling cascades inin vitroassays through several mechanisms, and this disrupted signaling is hypothesized to lead to dystonic motor symptoms in patients. However, the cells and circuits that mutations inGNALcorrupt are not well understood. Published patterns of Gαolfexpression outside the context of the striatum are sparse, conflicting, often lack cell type specificity, and may be confounded by expression of the closeGNALhomolog ofGNAS. Here, we use RNAScope in-situ hybridization to quantitatively characterizeGnalmRNA expression in brain tissue from wildtype C57BL/6J adult mice. We observed widespread expression ofGnalpuncta throughout the brain, suggesting Gαolfis expressed in more brain structures and neuron types than previously accounted for. We quantify transcripts at a single cell level, and use neuron type specific markers to further classify and understand patterns ofGNALexpression. Our data suggests that brain regions classically associated with motor control, initiation, and regulation show the highest expression ofGNAL, with Purkinje Cells of the cerebellum showing the highest expression of any neuron type examined. Subsequent conditionalGnalknockout in Purkinje cells led to markedly decreased intracellular cAMP levels and downstream cAMP-dependent enzyme activation. Our work provides a detailed characterization ofGnalexpression throughout the brain and the biochemical consequences of loss of Gαolfsignalingin vivoin neurons that highly expressGnal.