The long-term goal of this project is the development of genetic approaches to treat neurodegenerative diseases particularly Parkinson's disease. In addition to gene transfer experiments, we are studying transcription control of genes relevant to Parkinson's disease which would provide the requisite basic knowledge for their future manipulation for therapeutic intent. During FY97 we focused on the dopamine receptors expressed in the striatum. We had previously discovered that the human D1A dopamine receptor gene is transcribed from two promoters, one active only in brain while the other is active in both brain and kidney. During FY98 we continued our efforts to identify the nuclear factors that activate the brain-specific promoter, Two such transcription factors were cloned which are being characterized functionally. We had also found that the D2 dopamine receptor is under strong negative transcriptional control mediated through SP1/Sp3 binding to their consensus sequence. In the course of searching for other factors binding to Sp1 sites, we have cloned a novel zinc-finger protein that is highly expressed in the mouse striatum. Current efforts attempt to characterize the functional significance of this novel factor. During FY98 we found that the D3 dopamine receptor gene has two additional upstream exons that had been unrecognized thus far. Its functional promoter has been localized and is being studied in primary neuronal cultures. For our gene transfer studies, we have carried out proof-of-principle experiments and transferred the GDNF cDNA into the primate-MPTP model using encapsulated engineered cells and into the mouse-MPTP model using bone marrow progenitor cells. GDNF is a potent neurotrophic factor for dopaminergic neurons. The results which are still under analysis appear encouraging. Finally, since point mutations in the alpha-synuclein gene have been associated with autosomal dominant parkinsonism, we have studied the degradation of this presynaptic protein and found it to be processed by the ubiquitin-proteasome pathway. Detailed elucidation of this protein's fate could lead to understanding the pathogenesis of the neuropathology of Parkinson's disease.