[Polynucleotide sequences in the DNA from leukemic cells forming RNAse-resistant complexes with polyuridylic acid]

RNAase-resistant complexes of poly(U): poly (dA) were obtained by hybridization of [3H] poly (U) with cellular DNA. Depending on the mode by hybrids treatment with RNAase, two types of (dA)-sites i. el, dA and poly (dA) sites with different homogeneity were identified. The amount of these sequences in the DNA isolated from normal cells of intact animals and from several types of leukemic cells was determined. Full identity of the dA-sites in normal tissue DNAs of the same animals and a statistically significant increase in their content in leukemic cells were demonstrated. Differences between DNAs of normal and leukemic cells vary widely, depending on the leukemia type.