Antibodies specific for purine and pyrimidine nucleosides: Effect on in vitro priming ability of DNA

Abstract

Antibodies specific for thymine and guanine nucleosides react immunochemically with denatured but not with native DNA. These antibodies inhibit the ability of calf thymus DNA to serve as a primer for DNA polymerase extracted from chick embryos. No inhibition of DNA synthesis is observed with anti-bovine serum albumin or normal sheep globulin. Anti-T is more inhibitory than anti-G whether Bacillus cereus, Micrococcus lysodeikticus or calf thymus DNA preparations are used as primers. Purified anti-T inhibits the priming of DNA to the same extent, relative to antibody content, as the globulin fraction anti-T. The data are consistent with the hypothesis that binding of the anti-nucleoside antibodies to the exposed bases in denatured DNA prevents these masked regions from acting as templates for the DNA polymerase.