Studies On The Conservative Functions Of Primate SAMHD1

Objective:To discuss the antiviral effect,the inhibitory effect on LINE-1 restrotranson activity and the redection of interferon production signal pathway of primate SAMHD1,and to provide the basis for further study of primate SAMHD1.Method:The U937 cells stably expressing the primate SAMHD1 were established;the U937-control cells established with plvx-puro were used as negative control group,and the U937-SAMHD1 cells were treated with PMA to induce cell differentiation.The virus infection rates of HIV-1 in the cells in various groups were determined by flow cytometry.The HEK293 T cells transfected with the expression plasmid of SAMDH1 were used as a control group,and the cells were co-transfected with SAMHD1 and HIV-2/SIV Vpx expression plasmids were used as experimental groups.The cells were obtained 48 h after transfection,and the expression levels of SAMHD1 were determined by Western blotting.The intracellular location of SAMHD1 was determined by immunofluorescence.The HEK293 T cells transfected with LINE-1-GFP report plasmids were used as control group,and the cells co-transfected with LINE-1-GFP and SAMHD1 expression plasmids were used as experimental groups.The rates of GFP positive cells were determined by flow cytometry.The HEK293 T cells transfected with IFN-Luc report plasmids were used as control group,and the cells co-transfected with IFN-Luc and pSAMHD1 expression plasmids were used as experimental groups.The expression levels of luciferase in HEK293 T cells were determined by chemiluminescence instrument.Results:Compared with negative control group,the virus infection rates of HIV-1 in experimental groups with stable expression of SAMHD1 in the primates were significantly decreased in antiviral experiments(P<0.01).Compared with control group,the expression levels of SAMHD1 protein of the primates in experimental groups were decreased.(P<0.05 or P<0.01).The immunofluorescence results showed that the primate SAMHD1 was localized in the nucleus.Compared with control group,the rates of GFP positive cells(activity of SAMHD1 to LINE-1 transposon)in experimental groups were significantly decreased(P<0.05 or P<0.01).Compared with control group,the expression levels of luciferase in the HEK293 T cells in experimental groups were significantly decreased(P<0.05).Conclusion:The SAMHD1 protein of the different primates can resist the HIV-1 infection,inhibit the LINE-1 retrotransposon and antagonize the IFN production by natural immune system.