α Regulates Biochemical Signaling in Neurons Associated with Movement Control and Initiation.

The heterotrimeric G-protein α subunit, Gα , 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 the gene, which encodes Gα , have been identified as causative for an adult-onset dystonia. These mutations disrupt GPCR signaling cascades in assays through several mechanisms, and this disrupted signaling is hypothesized to lead to dystonic motor symptoms in patients. However, the cells and circuits that mutations in corrupt are not well understood. Published patterns of Gα expression outside the context of the striatum are sparse, conflicting, often lack cell type specificity, and may be confounded by expression of the close homolog of . Here, we use RNAScope in-situ hybridization to quantitatively characterize mRNA expression in brain tissue from wildtype C57BL/6J adult mice. We observed widespread expression of puncta throughout the brain, suggesting Gα is 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 of expression. Our data suggests that brain regions classically associated with motor control, initiation, and regulation show the highest expression of , with Purkinje Cells of the cerebellum showing the highest expression of any neuron type examined. Subsequent conditional knockout in Purkinje cells led to markedly decreased intracellular cAMP levels and downstream cAMP-dependent enzyme activation. Our work provides a detailed characterization of expression throughout the brain and the biochemical consequences of loss of Gα signaling in neurons that highly express .