Expression of α-synuclein from an episomal plasmid
The results seen on plates (A), above (where α-synuclein protein expression is switched on in the presence of both galactose and glucose), growth of yeast cells, (harbouring the episomal plasmid, pSYE239/α-synuclein-HA) (1) and (harbouring the episomal control plasmid, pSYE239) (2), on minimal medium solid agar plates that contained either glucose (SD) or galactose (SG). Clearly show that human α-synuclein, when expressed from an episomal 2-micron (2µ) plasmid, does not stop cell growth and therefore is not toxic to yeast. (B) Shows that a strain expressing α-synuclein from an episomal 2-µ plasmid also grows in liquid cultures. Compared with the control strain, there is no significant retardation of growth. Outeiro and Lindquist (2003) have reported that yeast cells expressing GFP-tagged α-synuclein from a 2µ plasmid also grew when expressed from the galactose-inducible GAL promoter. Expression of α-synuclein, controlled by the MET25 promoter, from a 2µ plasmid also did not inhibit cell growth [22].