ABSTRACT
To control thrombopoietin (TPO) expression by doxycycline in CHO cells, Tet-On gene expression system was used. Recombinant plasmid pTRE-TPO was successfully constructed. pTRE-TPO and pTK-Hyg were cotransfected into CHO-Tet-On cells. Cells resistant to hygromycin were cloned, high expression and low background clone was selected, and named as CHO-Tet-On-TPO. There was no significant TPO expression in the absence of doxycycline, the TPO level in the cell culture supernatant was 0.1 micro g/L. After exposure to 2 mg/L doxycycline, TPO expression was greatly increased, the TPO level in the cell culture supernatant reached 10.8 micro g/L. Tet-On gene expression system is a ready access to the tight-regulated and high-level gene expression system. It is likely to provide a safe and regulatable way for TPO gene therapy.