Figure 9.

Mutations of Ser¹⁶ and Ser⁴⁶ of Tat reduce its transactivation potential. A, COS-7 cells were transfected with WT Tat, Tat S16A, Tat S46A or Tat S16,46A expression vectors. At 48 hours posttransfection, the cells were lysed. Tat was immunoprecipitated from the lysates with rabbit polyclonal antibodies, resolved by 15% Tris-Tricine SDS-PAGE and immunoblotted with monoclonal anti-Tat antibodies. B, HeLa cells were transfected with the HIV-1 LTR-LacZ expression vector alone (not shown here) and in combination with WT Tat, Tat S16A, Tat S46A or Tat S16,46A expression vectors. At 48 hours posttransfection, cells were lysed and analyzed for β-galactosidase activity with ONPG.