Vpr but not Vpx down-regulates MUS81.
A, MUS81 was transiently co-transfected with increasing amounts of VprHIV-1 NL4-3. At 48 h post-transfection, cells were harvested and analyzed by Western blotting. B, MUS81 was co-transfected with increasing amounts of EME1 and empty vector or Vpr HIV-1 NL4-3 plasmids. The same amounts of MUS81 and EME1 plasmids were used for lanes 1 and 5, lanes 2 and 6, lanes 3 and 7, and lanes 4 and 8. C, HEK293T cells were transfected with increasing amounts of VprHIV-1 NL4-3 plasmid. The endogenous level of MUS81 was analyzed by Western blotting. D, MUS81 or SAMHD1 was co-transfected with an increasing amount of VpxSIVmac. E, HEK293T cells were incubated with 20 μg/ml cycloheximide, 40 h after transfection with the indicated plasmids. The levels of MUS81 and Vpr were analyzed by Western blotting after the indicated times. The intensity of bands corresponding to MUS81 and Vpr were quantified from four independent experiments.