FIG. 2.

Colocalization of Sp1 and Tat in transfected HeLa cells. (A) Tat localization in HeLa cells transfected with Tat expression plasmid and stained in parallel for Tat (anti-Tat rabbit primary antibody and Texas red-conjugated goat anti-rabbit second antibody) and SC35 (anti-SC35 mouse monoclonal primary antibody and FITC-conjugated goat anti-mouse second antibody). In panel A, only the Tat visualization window is shown. (B) Visualization of SC35 in the cell shown in panel A. (C) Computer colocalization analysis of the signals shown in panels A and B, with Tat staining indicated by red and SC35 staining indicated by green. Areas of colocalization are indicated in yellow. (D) Tat localization in HeLa cells transfected with Tat expression plasmid and stained in parallel for Tat (anti-Tat rat primary antibody and Texas red-conjugated goat anti-rat second antibody) and Sp1 (rabbit anti-Sp1 primary antibody and FITC-conjugated goat anti-rabbit second antibody). Only the Tat window is shown. (E) Visualization of Sp1 in the cell shown in panel D. (F) Colocalization analysis of panels D and E, with Tat staining highlighted by red and Sp1 staining highlighted by green. Areas of colocalization between Tat and Sp1 are indicated in yellow. (G) Additional views of cells transfected with a Tat-expressing plasmid and stained with rat antiserum to Tat and rabbit polyclonal antiserum to Sp1. The confocal image capture window was set for the anti-Tat signal. (H and I) Computer-assisted colocalization of Tat and Sp1 signals shown in black (H) and red (I). (J) Confocal micrograph with fluorescence window adjusted to capture anti-Tat (red), anti-Sp1 (green), and colocalized images of the two proteins (yellow). This field of cells is identical to that in panel G. (K and L) Lower-magnification views of the same field of cells transfected with a Tat-expressing plasmid stained with rat anti-Tat and rabbit anti-Sp1. The fluorescence image capture window was restricted to either anti-Tat (K) or anti-Sp1 (L).