ESTABLISHMENT AND CHARACTERIZATION OF A MONOCLONAL-ANTIBODY RECOGNIZING THE DEWAR ISOMERS OF (6-4)PHOTOPRODUCTS

We established a monoclonal antibody (DEM-1) that recognizes UV-induce d DNA damage other than cyclobutane pyrimidine dimers or (6-4)photopro ducts. The binding of DEM-1 antibody to 254 nm UV-irradiated DNA incre ased with subsequent exposure to UV wavelengths longer than 310 nm, wh ereas that of the 64M-2 antibody specific for the (6-4)photoproduct de creased with this treatment. Furthermore, the increase in DEM-1 bindin g was inhibited by the presence of the 64M-2 antibody during the expos ure. We concluded that the DEM-1 antibody specifically recognized the Dewar photoproduct, which is the isomeric form of the (6-4)photoproduc t. The DEM-1 antibody, however, also bound to DNA irradiated with high fluences of 254 nm UV, suggesting that 254 nm UV could induce Dewar p hotoproducts without subsequent exposure to longer wavelengths of UV. Furthermore, an action spectral study demonstrated that 254 nm was the most efficient wavelength for Dewar photoproduct induction in the reg ion from 254 to 365 nm, as well as cyclobutane dimers and (6-4)photopr oducts, although the action spectrum values in the UV-B region were si gnificantly higher compared with those for cyclobutane dimer and (6-4) photoproduct induction.