α-Synuclein (αSN) in human is tightly linked both neuropathologically and genetically to Parkinson's disease (PD) and related disorders. Disease-causing properties in vivo of the wildtype mouse ortholog (mαSN), which carries a threonine at position 53 like the A53T human mutant version that is genetically linked to PD, were never reported. To this end we generated mouse lines that express mαSN in central neurons at levels reaching up to six-fold compared to endogenous mαSN. Unlike transgenic mice expressing human wildtype or mutant forms of αSN, these mαSN transgenic mice showed pronounced ubiquitin immunopathology in spinal cord and brainstem. Isoelectric separation of mαSN species revealed multiple isoforms including two Ser129-phosphorylated species in the most severely affected brain regions. Neuronal Ser129-phosphorylated αSN occured in granular and small fibrillar aggregates and pathological staining patterns in neurites occasionally revealed a striking ladder of small alternating segments staining either for Ser129-phosphorylated αSN or ubiquitin but not both. Axonal degeneration in long white matter tracts of the spinal cord, with breakdown of myelin sheaths and degeneration of neuromuscular junctions with loss of integrity of the presynaptic neurofilament network in mαSN transgenic mice, was similar to what we have reported for mice expressing human αSN wildtype or mutant forms. In hippocampal neurons, the mαSN protein accumulated and was phosphorylated but these neurons showed no ubiquitin immunopathology. In contrast to the early-onset motor abnormalities and muscle weakness observed in mice expressing human αSN, mαSN transgenic mice displayed only end-stage phenotypic alterations that manifested alongside with neuropathology. Altogether these findings show that increased levels of wildtype mαSN does not induce early-onset behavior changes, but drives end-stage pathophysiological changes in murine neurons that are strikingly similar to those evoked by expression of human wildtype or mutant forms.

α-Synuclein (αSYN) is the neuropathological hallmark protein of Parkinson's disease (PD) and related neurodegenerative disorders. Moreover, the gene encoding αSYN (SNCA) is a major genetic contributor to PD. Interestingly, independent genome-wide association studies also identified SNCA as the most important candidate gene for alcoholism. Furthermore, single-nucleotide-polymorphisms have been associated with alcohol-craving behavior and alcohol-craving patients showed augmented αSYN expression in blood. To investigate the effect of αSYN on the addictive properties of chronic alcohol use, we examined consumption, motivation, and seeking responses induced by environmental stimuli and relapse behavior in transgenic mice expressing the human mutant [A30P]αSYN throughout the brain. The primary reinforcing effects of alcohol under operant self-administration conditions were increased, while consumption and the alcohol deprivation effect were not altered in the transgenic mice. The same mice were subjected to immunohistochemical measurements of immediate-early gene inductions in brain regions involved in addiction-related behaviors. Acute ethanol injection enhanced immunostaining for the phosphorylated form of cAMP response element binding protein in both amygdala and nucleus accumbens of αSYN transgenic mice, while in wild-type mice no effect was visible. However, at the same time, levels of cFos remain unchanged in both genotypes. These results provide experimental confirmation of SNCA as a candidate gene for alcoholism in addition to its known link to PD.

We have conducted a screen to identify developmentally regulated enhancers that drive tissue-specific Gal4 expression in zebrafish. We obtained 63 stable transgenic lines with expression patterns in embryonic or adult zebrafish. The use of a newly identified minimal promoter from the medaka edar locus resulted in a relatively unbiased set of expression patterns representing many tissue types derived from all germ layers. Subsequent detailed characterization of selected lines showed strong and reproducible Gal4-driven GFP expression in diverse tissues, including neurons from the central and peripheral nervous systems, pigment cells, erythrocytes, and peridermal cells. By screening adults for GFP expression, we also isolated lines expressed in tissues of the adult zebrafish, including scales, fin rays, and joints. The new and efficient minimal promoter and large number of transactivating driver-lines we identified will provide the zebrafish community with a useful resource for further enhancer trap screening, as well as precise investigation of tissue-specific processes in vivo.