Non-radioactive labeling and detection of nucleic acids. IV. Synthesis and properties of digoxigenin-modified 2'-deoxyuridine-5'-triphosphates and a photoactivatable analog of digoxigenin (photodigoxigenin).

The chemical syntheses of novel digoxigenin-derivatized compounds are described which are modified substrates for enzymatically or photochemically non-radioactive digoxigenin labeling of nucleic acids. Various activated digoxigenin-haptens are coupled to 5-aminoallyl-substituted 2'-deoxyuridine-5'-triphosphate. This results in digoxigenin-modified nucleoside triphosphates of variable spacer lengths (Dig-[4]-dUTP/Dig-[11]-dUTP/Dig-[16]-dUTP) which can be used as substrates for enzymatic labeling of DNA with digoxigenin-haptens by Klenow enzyme-catalysed random-primed synthesis. In addition the synthesis of N-[4-azidobenzoyl]-N'-[(3-O-digoxigeninyl)methylcarbonyl)]-1 ,8-diamino- 3,6-dioxaoctane (photodigoxigenin), a photoactivatable analog of digoxigenin, is described which can be applied for photolabeling of DNA and RNA with digoxigenin-haptens leaving the nucleic acid molecules intact.