Hybridization of polyuridylic acid to human DNA immobilized onto nitrocellulose filters

Abstract
The level of deoxyadenylate (dA) regions in human DNA was estimated from formation of poly(U)-poly(dA) triplexes on nitrocellulose filters that were RNAase resistant. The (dA) rich sequences were determined following mild ribonuclease treatment of the poly(U)-DNA hybrids (5 μg/ml at 25°C for 30 min), where as exhaustive ribonuclease treatment (5 μg/ml at 25°C for 6 hr) estimated the more (dA) pure sequences. The level of (dA) rich regions was 0.39% of the DNA and for the more (dA) pure regions it was 0.07%.