Monoclonal antibodies specific for poly(dG) X poly(dC) and poly(dG) X poly(dm5C).
Most duplex DNAs that are in the "B" conformation are not immunogenic. One important exception is poly(dG) X poly(dC), which produces a good immune response even though, by many criteria, it adopts a conventional right-handed helix. In order to investigate what features are being recognized, monoclonal antibodies were prepared against poly(dG) X poly(dC) and the related polymer poly(dG) X poly(dm5C). Jel 72, which is an immunoglobulin G, binds only to poly(dG) X poly(dC), while Jel 68, which is an immunoglobulin M, binds approximately 10-fold more strongly to poly(dG) X poly(dm5C) than to poly(dG) X poly(dC). For both antibodies, no significant interaction could be detected with any other synthetic DNA duplexes including poly[d(Gm5C)] X poly[d(Gm5C)] in both the "B" and "Z" forms, poly[d(Tm5Cm5C)] X poly[d(GGA)], and poly[d(TCC)] X poly[d(GGA)], poly(dI) X poly(dC), or poly(dI) X poly(dm5C). The binding to poly(dG) X poly(dC) was inhibited by ethidium and by disruption of the DNA duplex, confirming that the antibodies were not recognizing single-stranded or multistranded structures. Furthermore, Jel 68 binds significantly to phage XP-12 DNA, which contains only m5C residues and will precipitate this DNA in the absence of a second antibody. The results suggest that (dG)n X (dm5C)n sequences in natural DNA exist in recognizably distinct conformations.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D001667:Binding, Competitive; D002417:Cattle; D004247:DNA / Q000276:immunology; D004279:DNA, Viral / Q000276:immunology; D006358:Hot Temperature; D009691:Nucleic Acid Denaturation; D011089:Polydeoxyribonucleotides / Q000276:immunology*
D000911:Antibodies, Monoclonal; D004279:DNA, Viral; D011089:Polydeoxyribonucleotides; C016681:poly(dG).poly(dC); C029988:poly(dG-m(5)dC).poly(dG-m(5)dC); D004247:DNA