Abstract
Dopamine (DA) is an essential neurotransmitter that mainly involved in motor control, learning and cognitive association. The dysfunction of DA system links to several human diseases, including Parkinson’s disease (PD). However, the pathogenic mechanism of this disease is still unclear. To determine whether the imbalance of cellular DA level is involved in PD pathogenesis, it is essential to develop a genetically amenable probe that can directly detect intracellular DA in vivo. Here we utilize the unique spectrum feature of MAO B to design a MAO B-split GFP fusion protein as a DA probe. MAO B is a redox enzyme that catalyses catecholamine oxidation. In the absence of substrate, MAO B is at oxidized form that can absorb 400-500nm spectrums. Upon DA binding to MAO B, MAO B is reduced and losses this absorption property. Therefore, the elicit of GFP signal can serve as a readout of DA. We show that indirect modulations of cellular DA can trigger GFP fluorescence emission of the probe, suggesting this probe is feasible for DA detection. By applying this probe to PD models, we may be able to determine whether cellular DA imbalance is responsible for regional vulnerability of PD and other DA system related psychiatric disorders.