Thymosin Alpha <sub> 1 </ Sub> Gene Expression Vector And Its Expression In Pichia Pastoris

Human thymosin α1 (hTαl) which has immunopotentiating and immunotherapeutic effects, has been reported to be very useful in clinical applications. The development of biotechnology provides a new way to produce hTal. The Pichia pastoris expression system was applied to study the expression of hTal.The hTal gene was synthesized using optimal codons of Pichia pastoris. The fusion gene of hTαl-RP was got by ligating hTal and the N-terminal of ribosom protein (RP) gene. The hTal gene and the fusion gene were inserted into the expression vector pPIC3.5K and pPIC9K and were transfered into HIS4 mutant strain GS115. The transfermants with the highest resistance to G418 (4mg/ml in YPD) was screened to obtain the strain with high expression level.Induced with methanol, the GS115/pPIC3. 5K/ hTαl-RP expressed the fusion protein in the yeast cell. Both SDS-PAGE and Western blot indicated that this fusion protein was expressed. The expression level was about 25mg/ml.