Comparing cytosolic expression to peroxisomal targeting of the chimeric L1/L2 (ChiΔH-L2) gene from human papillomavirus type 16 in the methylotrophic yeasts Pichia pastoris and Hansenula polymorpha

The chimeric Chi?H-L2 gene from human papillomavirus type 16, consisting of structural proteins L1 and L2, was successfully expressed in the cytosol of both Pichia pastoris and Hansenula polymorpha during methanol induction. In addition, a novel approach was employed whereby Chi?H-L2 was targeted to the peroxisome using peroxisomal targeting sequence 1 (PTS1) to compare Chi?H-L2 yields in the peroxisome vs the cytosol. The Chi?H-L2 gene was yeast-optimized and cloned into plasmids aimed at genomic integration. Levels of intracellular Chi?H-L2 accumulation in the cytosol were highest in P. pastoris KM71 strain KMChi?H-L2 (1.43?mg/l), compared to the maximum production level of 0.72?mg/l obtained with H. polymorpha. Chi?H-L2 targeting to the peroxisome was successful; however, it appeared to negatively affect Chi?H-L2 production in both P. pastoris and H. polymorpha. Copyright (C) 2012 John Wiley & Sons, Ltd.