Pab 1801 puncta are present in p53-null cells.

<p>A, B, p53+/+ or p53−/− HCT116 cells were treated with daunorubicin and immunostained with the Pab 1801 (A) or the Pab DO1 (B). With both antibodies, a nuclear signal is observed upon stimulation of p53+/+ cells but not p53−/− cells. Pab 1801-positive puncta are always present in p53+/+ and p53−/− cells independently of p53 levels. C, p53-null H1299 cells were treated with the indicated drugs and stained with the Pab 1801. The Pab 1801 puncta disappeared upon exposure to cycloheximide and remained unaltered after puromycin treatment. The percentage of cells with punctate Pab 1801 signal was evaluated in 100 cells from duplicate stainings for each treatment. Bar, 10 µm. D, alignment of human and rat p53 N-terminus including the Pab 1801 epitope (grey box). The 10-aa epitope is absent in the rat sequence. E, Hippocampal rat neurons were prepared as described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036447#pone.0036447-Baez2" target="_blank">[27]</a> and stained with the Pab 1801 or the Pab DO1. A merge of the immunofluorescence and the phase contrast images is shown. Pab 1801-positive puncta are detected in cell soma and dendrites. Bars, whole cells, 10 µm; magnifications, 1 µm.