The binding of 8-methoxypsoralen to nuclear DNA of UVA irradiated human fibroblasts in vitro.

Human fibroblasts were exposed to tritium-labelled 8-methoxypsoralen (8-MOP) and longwave ultraviolet (UVA) light in vitro. The proportions of photochemically bound 8-MOP in the nucleus and cytoplasm were studied by autoradiography. The results show that UVA-irradiation of the cells in the presence of 8-MOP gives rise to a significant dose-dependent binding of 8-MOP in the cell nucleus.