Nuclear localization of ZnPP and SnPP in HA-1 cells.

Representative pseudoimages of fluorescent signal for MPs and immunoreactive p53. Three slides in each group were incubated with ZnPP or SnPP then incubated with p53 antibody and FITC-labeled secondary antibody as described in “Materials and methods” and analyzed at various time points. The MPs were visualized using their endogenous fluorescence by setting excitation at 568 nm and emission at more than 590 nm, and FITC was detected by setting the excitation at 488 nm and the emission at 515 to 545 nm. Upper panel is ZnPP-incubated HA-1 cells. Lower panel shows SnPP-incubated HA-1 cells. Lane 1h, 1-hour incubation with MP; lane 4h, 4-hour incubation with MP; lane 12h, 12-hour incubation with MP; lane 24h, 24-hour incubation with MP. The yellow arrows represent colocalization of MPs and p53; the orange arrow represents the endogenous fluorescence of the MPs; the green arrow represents the p53 signal. In the SnPP-treated cells, the FITC signal was further enhanced to allow for visualization of p53 within the nucleus. Note the nuclear colocalization of ZnPP and p53 and the lack of nuclear colocalization of SnPP and p53. CrPP could not be visualized due to a lack of endogenous fluorescence.