FIG. 1.

Construction and infectivity of proviral clones carrying a tagged IN. (A) Sequences encoding the epitope tags were inserted by PCR either near the N or at the C terminus of IN with the HIV-1 BRU infectious molecular clone, yielding the indicated proviral clones. RT, reverse transcriptase. (B) Infectivity of the wild-type BRU and of the tagged clones was measured in a single-cycle assay on P4 (HeLa-CD4⁺, LTR-LacZ) cells. Values are expressed as percentages of the BRU virus and represent the means and the standard deviations of four independent experiments. (C) Viral infectivity measured as the accumulation of the HIV-1 antigen p24 in the supernatant of MT4 cells.