A recombinant expressing plasmid pCMV4/TPO was also constructed by cloning the rhTPO cDNA in an eukaryotic expressing vector pCMV4. When the recombinant plasmid was used to transfect the COS7 cells, temporary expression of rhTPO was detected.

• 将TPOcDNA亚克隆至哺乳动物细胞瞬时表达载体pCMV4，形成了重组表达质粒pCMV4/TPO。 以该重组质粒转染COS7细胞，可测到TPO在COS7细胞中的瞬时表达