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. 2002 Mar;13(3):915–929. doi: 10.1091/mbc.01-08-0383

Figure 4.

Figure 4

FBI-1, HIV-1 Tat, and TAK/P-TEFb localization. (A) Epifluorescent image of HeLa cells transfected with HA-Tat expressing plasmid. FBI-1 (panel 1, green) and HA-Tat (panel 2, red) colocalize (panels 3 and 4, yellow) at numerous foci within the nonnucleolar nucleoplasm. Endogenous FBI-1 was detected with a rabbit polyclonal (413) primary antibody and fluorescein isothiocyanate (FITC)-conjugated goat anti-rabbit secondary antibody (FITC-GAR). HA-Tat was detected with a mouse monoclonal (12CA5) primary antibody and a Texas Red-conjugated Goat anti-mouse secondary antibody (TR-GAM). (B) Epifluorescent image of HeLa cells transfected with 2 μg of HA-Tat expressing plasmid (panel 1) or mock transfected (2 μg of expression vector) HeLa cells (panels 2 and 3). HA-Tat (panel 1, column 1, green), endogenous cyclin T1 (panel 2, column 1, green) and Cdk9 (panel 3, column 1, green) and nuclear speckles (panels 1–3, column 2, red) colocalize (panels 1–3, column 3 and 4, yellow) at numerous irregularly shaped foci within the nonnucleolar nucleoplasm. HA-Tat was detected with 12CA5 primary antibody and an FITC-conjugated goat anti-mouse secondary (FITC-GAM). Cyclin T1 was detected with a rabbit polyclonal (anticyclin T1) antibody and FITC-GAR secondary. Cdk9 was detected with a rabbit polyclonal (anti-Cdk9) antibody and FITC-GAR secondary. Nuclear speckles were detected with a human polyclonal (ANA-S; panel 1) primary antibody or a mouse monoclonal (SC35) primary antibody and with Texas Red–conjugated goat anti-human antibody (TR-GAH) and TR-GAM, respectively. (C) Epifluorescent image of HeLa cells. Endogenous FBI-1 (green) displays a heterogeneous nuclear localization pattern characterized by numerous signal foci that surround and overlap with the nuclear speckle domain (red). Note that often there is a slight decrease in signal within a FBI-1 foci that matches the shape of the corresponding speckle (panel 2, arrowheads). FBI-1 was detected with 413 primary and FITC-GAR secondary antibodies, and nuclear speckles were detected with SC35 primary and TR-GAM secondary antibodies.