CELL MEMBRANE DNA: A NEW TARGET FOR PSORALEN PHOTOADDUCT FORMATION

Abstract

The effects of 8‐methoxypsoralen plus long wavelength ultraviolet radiation on cell membrane DNA were examined. Treatment of human lymphocytes with 100 ng/ml 8‐methoxypsoralen and 5 J/cm² UVA led to the formation of 7.1 ±3.8 photoadducts per million bases. A monoclonal antibody, specific for 8‐methoxypsoralen 4′,5′4nonoadducts, was used to detect photoadducts in the cell membrane DNA of human lymphocytes and three lymphoblastoid cell lines. Treatment of lymphocytes with 8‐MOP and UVA reduced the lymphocyte DNA binding capacity by 56%. Cell membranes of normal lymphocytes were shown to contain three high affinity DNA binding proteins of 28, 59, and 79 kDa, respectively.