Fig. (2) Analysis of CHI-E7p protein expressed in yeast and human cells. (a) Transmission electron microscopy of negatively stained CHI-E7p VLPs purified by ion metal affinity chromatography (Ni-NTA-agarose columns) from the yeast P. pastoris transformed with the pPICZ(A)-CHI-E7p plasmid. The VLPs appear as nanoparticles of 20-25 nm in diameter. (b) Western blot of HEK293 cells transfected transiently with pcDNA3 plasmids encoding either the CHI-E7p or the H-E7p fusion proteins. The cells were lysed and electrophoresed 48 hours after transfection. The proteins were detected with anti-6x His antibodies. The CHI-E7p protein runs with a molecular weight of ~55 kDa while the H-E7p protein appears as a ~28 kDa band.