Positions of chromosome territories in normal and DNA-damaged human lung fibroblasts. The positions of chromosomes 11, 12, 15, 17 and 19 were delineated in normal human lung fibroblasts before and after DNA damage, and after 24 hours of recovery from damage. (A, D, I, B, G, L) As in normal human dermal fibroblasts, chromosomes 17 and 19 reposition from the nuclear interior to the periphery. (B, F, K, C, H, M) Chromosomes 12 and 15 relocate from the nuclear periphery to the interior after damage. On recovery, these chromosomes revert to their native locations after 24 hours (A, B and C and blue bars in panels D–M). Chromosome 11 does not show any relocation after DNA damage (A, E and J). Scale bar: 10 μm. Error bars represent SEM. * indicates P = 0.05.