Figure 2

SAMHD1 restricts HIV-1, FIV, SIV and EIAV infection in THP-1 cells. (A) Differentiated THP-1 shSAMHD1, shControl or THP-1 wild-type cell lysates were analyzed on an immunoblot probed with anti-SAMHD1 MAb or anti-GAPDH MAb. (B) THP-1 shSAMHD1 and control cells were differentiated with PMA, preincubated with VLP and infected with HIV-GFP reporter virus at a MOI = 1. (C) THP-1 control or shSAMHD1 cells transduced with a lentiviral vector coding for shRNA-resistant SAMHD1, the catalytic-inactive mutant SAMHD1 HD-AA or empty vector (none), were differentiated then pretreated with Vpx-containing or control VLP and infected with HIV-luciferase reporter virus. Luciferase activity was measured three days postinfection and is shown as fold enhancement by Vpx-VLP treatment. (D) Quantification of dATP and dTTP nucleotide levels in differentiated SAMHD1 knock-down and control THP-1 cell lines. In (E), (F) and (G) Control or SAMHD1 knock-down THP-1 cells were differentiated with PMA, preincubated with Vpx-containing (+Vpx) or control VLP (−Vpx), and infected with (E) FIV-GFP, (F) with SIV-ΔVpx-luc, or (G) EIAV-RFP reporter virus. Reporter virus infection was quantified three days later by flow cytometry or luciferase assay. The data shown are the average of triplicate infections with error bars indicating the standard deviation.