FIG. 4.

Mapping the Vpr phosphorylation sites. (A) Schematic representations of HIV-1 NL4-3 Vpr and various mutations. Serines at positions 28, 79, 94, and 96 were mutated to alanines. Dashes indicate amino acid residues that are the same as in Vpr(NL4-3); Vpr(SRIG) is a SRIG deletion mutant. (B) Wild-type Vpr and relevant mutants were expressed in BSC40 cells using the vaccinia virus expression system. The cells were labeled with ³⁵S or ³²P overnight, and labeled Vpr was detected with anti-Vpr antibodies.