A dose-dependent expression of humanized recombinant green fluorescent protein (hrGFP) gene.

<p>HeLa cells and human bone marrow-derived mesenchymal stem cells (hMSCs) were co-transduced with binary Tet-On lentivirus vectors harboring both the human glial cell line-derived neurotrophic factor (hGDNF) and hrGFP genes. The virus vector-containing medium was replaced with the medium in the presence (On) or absence (Off) of doxycycline (Dox) 8 hour after transduction. Serial doses of Dox ranging from 10⁻⁴ – 10⁴ ng/ml were tested to induce transgene expression. The cells were harvested and mean fluorescence intensity (MFI) units for hrGFP were examined by flow cytometry (FCM) 4 days after Dox treatment. The expression of hrGFP transgene in HeLa cells (A) and hMSCs (B) was regulated in a clear Dox dose-dependent manner.