Preliminary study on the regulation of KSHV latent infection by HIV-1 Vpr medicated by the recombinant lentivirus

Objective To package the recombinant lentivirus containing HIV-1 Vpr gene and detect the effect of Vpr protein expression on the latent infection and lyric replication of KSHV.Methods The fragment of Vpr gene from expression plasmid pCI-neo-Vpr was cloned into the lentivirus vector pHAGE-CMV-MCS-IzsGreen,then the recombinant plasmid pHAGE-Vpr,package vector psPAX2 and envelope vector pMD2.G were cotransfected into 293T cells.GFP expression was observed by fluorescent microscopy.Culture media of 293T cells were harvested and filtered through 0.45 μm filter.After 293T cells were infected by a series of diluted lentivirus,the virus titer was checked by observing GFP expression.Vpr mRNA transcripts in 293T cells were detected by RT-PCR.Then BCBL-1 cells were infected by the recombinant lentivirus with 1 MOI,GFP expression was observed by fluorescent microscopy,and the mRNA transcripts and protein expression of Vpr in BCBL-1 cells were detected by RT-PCR and Western blot.Meanwhile,the mRNA transcripts and protein expression of KSHV lytic cycle gene Rta were detected by RT-PCR and Western blot,respectively.Results The recombinant lentivirus carrying HIV-1 Vpr was packaged successfully with the virus titer of 4 × 107 TU/ml.After infected with lentivirus,BCBL-1 cells could express GFP,and the exact band of Vpr was detectable by RT-PCR and Western blot.Moreover,the expression of KSHV Rta mRNA and protein were downregulated by Vpr protein.Conclusion Overexpression of HIV-1 Vpr mediated by the recombinant lentivirus could inhibit KSHV lytic replication and enhance KSHV latent infection. Key words: Lentivirus; Viral protein R(Vpr); Kaposis's sarcoma-associated herpesvirus (KSHV); Replication