Figure 4.

Cellular uptake of FITC-conjugated NLS-A and FITC-conjugated HIV-TAT. A, PK15, HeLa, and NIH3T3 cells were incubated with FITC-conjugated NLS-A (upper row) or FITC-conjugated HIV-TAT (middle row) for 30 min and washed three times with PBS before imaging with a dual-channel confocal laser-scanning microscope (Nikon TiE). A third test with buffer only was used as a treatment control (bottom row). Green indicates FITC signal in the cells, and cell nuclei (blue) are indicated by Hoechst. B, bar graph summarizing the fluorescence intensity of the PK15, HeLa, and NIH3T3 cells under the above three incubation treatments (n = 4; error bars represent S.D.; ***, p < 0.001). All scale bars represent 10 μm. a.u., arbitrary units.