Molecular characteristics of porcine alpha-synuclein splicing variants

Alpha-synuclein (alpha-syn) is a 140 amino acid, intrinsically disordered protein with a potential role in neurotransmitter vesicle release. The protein is natively unfolded under physiological conditions, and is expressed predominantly in neural tissue. alpha-syn is associated with neuropathological conditions in Parkinson's disease, where the protein misfolds into oligomers and fibrils resulting in aggregates in Lewy bodies. Here we report the molecular cloning of SNCA cDNA encoding porcine alpha-syn and transcript variants hereof. Six transcripts coding for porcine alpha-syn are presented in the report, of which three result from exon skipping, generating in-frame splicing of coding exons 3 and 5. The splicing pattern of these alternative spliced variants is conserved between human and pig. All the observed in-frame deletions yield significantly shorter alpha-syn proteins compared with the 140 amino acid full-length protein. Expression analysis performed by real-time quantitative RT-PCR revealed a differential expression of the six transcript splicing variants in different pig organs and tissues. Common for all splicing variants, a very high transcript expression was detected in brain tissues and in spinal cord and very low or no expression outside the central nervous system. The porcine alpha-syn protein demonstrated markedly different biophysical characteristics compared with its human counterpart. No fibrillation of porcine alpha-syn was observed with the pig wild-type alpha-syn and A3OP alpha-syn, and both variants show significantly reduced ability to bind to lipid vesicles. Overexpression of mutated porcine alpha-syn might recapitulate the human PD pathogenesis and lead to the identification of genetic modifiers of the disease. (C) 2020 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.

Automated summary

Alpha-synuclein is a protein associated with neural tissue and Parkinson's disease pathogenesis. The identification of similar transcript variants in pigs, with high expression in brain tissues and low expression outside the central nervous system, suggests potential for modeling the disease in pigs and studying genetic modifiers. The biophysical characteristics of porcine alpha-synuclein differ from its human counterpart, with reduced ability to bind to lipid vesicles and no observed fibrillation.