Abstract: Objective To construct recombinant lentivirus carrying PML(?NLS) gene and observe its effect on the expression of c-Myc protein in leukemia NB4 cell lines. Methods PML(?NLS) gene was amplified by PCR using plasmid pCMV-HA-PML(?NLS) as a template and cloned into the lentivirus vector LV5-EF1a-GFP/puro.The recombinant lentiviral vector，pHelper 1.0 and pHelper 2.0 were co-transfected into 293T cells，packaging virus. Then NB4 cells were infected with the supernatant containing lentiviral particles，and its infection efficiency was determined by fluorescent microscope，PML(?NLS) mRNA transcription and protein expression in NB4 cells were determined by RT-PCR and Western blot respectively，the expression of ?-catenin，γ-catenin and c-Myc proteins in NB4 cells were analyzed by Western blot. Cell proliferation was detected by CCK-8. Results Recombinant lentivirus LV5-PML(?NLS) was successfully constructed. The infection efficiency in NB4 cells reached 82.74％，the PML(?NLS) gene in LV5-PML(?NLS) was expressed stably in NB4 cells； the expression of β-catenin, γ-catenin and c-Myc proteins were decreased in NB4 cells infected with LV5-PML(?NLS). The activity of cell proliferation in NB4 cells was significantly enhanced as compared to the untransfeced and empty viral groups. Conclusion Recombinant lentivirus LV5-PML(?NLS) was constructed successfully and efficiency infected in NB4 cells. In addition，it could inhibit the expression of c-Myc protein.

Key words: PML(NLS-), recombinant lentivirus, NB4 cells, c-Myc