Figure 4: Optical control of p53 transcriptional activity.
(a) Schematic of used vector for light control of human p53. NLS, cMycP1A NLS. (b) Fluorescence images and (c) corresponding quantification of the relative nuclear fluorescence over time of H1299 p53−/− cells transfected with the construct in a. Cells were irradiated with blue light pulses for 40 min following a 40-min dark-recovery phase (mean±s.d., n=20 cells). (b) Scale bar, 20 μm. (d) Flowchart showing blue light control of p53 transcriptional activity. (e) Western blot analysis of p21 and beta-actin levels and (f) corresponding quantification for H1299 p53−/− cells transiently transfected with p53-mCherry-LEXY or indicated control vectors and illuminated with blue light pulses for 48 h or incubated in the dark. NS, not significant; p53-LEXY, p53-mCherry-LEXY; p53-NES, p53-mCherry carrying a constitutive PKIt NES; wt p53, wild-type p53 fused to mCherry. (f) Mean±s.d., n=3 independent experiments; ***P=3.92 × 10−4 by Welch’s t-test.
