The role of nucleotide sequence in the immune-active structure photochemically induced in double-stranded DNA by ultraviolet irradiation.
Pyrimidine, purine, and mixed sequence oligonucleotides from ultraviolet-irradiated DNA were tested for their inhibitory activities on the interaction of [3H]ultraviolet-irradiated DNA with its antibody raised in rabbit. Thymine dimer containing pyrimidine oligonucleotides from irradiated DNA failed to inhibit the interaction, while mixed sequence oligonucleotides, especially those with 8 or more nucleotides, exhibited potent inhibition. Purine clusters from irradiated DNA and mixed sequence oligomers from unirradiated DNA showed no inhibition. Dimerized thymine, which appears to be a critical part of the antigenic determinant, did not inhibit the interaction by itself. The same observations were made for ultraviolet-irradiated thymidine and thymidylic acid. The results suggest that a structure composed of a mixed pyrimidine and purine sequence with a certain chain length seems to be essential for the antigenicity induced in the irradiated DNA. On this nucleotide chain backbone, photochemically modified bases (mostly thymine dimer) can form an immune-active structure.
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000276:immunology* / Q000528:radiation effects; D000939:Epitopes; D009838:Oligodeoxyribonucleotides / Q000302:isolation & purification; D010777:Photochemistry; D011817:Rabbits; D011863:Radioimmunoassay; D013936:Thymidine / Q000494:pharmacology; D013941:Thymine / Q000378:metabolism / Q000494:pharmacology; D014466:Ultraviolet Rays
D000939:Epitopes; D009838:Oligodeoxyribonucleotides; D004247:DNA; D013941:Thymine; D013936:Thymidine