Fig. 4. UV-induced colocalization of ING1 with PCNA but not with p53. Half of a set of Hs68 fibroblasts plated for 24 hours were treated with 25 J/m2 of UV, fixed 2 hours later and stained for DNA, ING1 and PCNA (a-h), or for DNA, ING1 and p53 (panels i-p). Confocal microscopy and calculation of the degree of colocalization was as described in Materials and Methods. Bar, 10 µm.