Eukaryotic Expression and Primarily Application of Human Smith D1 Antigen in Methylotrophic Yeast Pichia pastoris

Abstract:

To clone, express and primarily use human autoantigen Sm D1 in methylotrophic yeast Pichia Pastoris. The gene Sm D1 was cloned by PCR.The PCR product was inserted into the vector pPIC9k. The recombinant plasmid pPIC9k- Sm D1 was transformed into yeast SMD1168 by electroporation. The positive clones were screened in MD plates. The high copy number transformants were rapidly selected by using G418 and were induced by methanol. Supernatants after induction were analyzed by SDS-PAGE and immunodot. The PCR product was showed about 360 bp in size which was in accordance with predicted. The pPIC9k-Sm D1 showed the same seqencing result with GenBank’s report and restriction enzyme analysis confirmed our prediction. The pPIC9k-Sm D1 positive clone produced an about 16 kD protein which had natural immunogenicity of human autoantigen Sm D1 by SDS-PAGE and immunodot. The sensitivity and specificity of immunodot were 96% and 100%, respectively. The agreement between immunodot and immunoblot was 98%. Successfully cloning and high-level expression of human autoantigen Sm D1 in methylotrophic yeast Pichia pastoris laid a foundation for further research work.