title: Identification of human DNA sequences complementary to chromosomal RNA with an improved RNA/DNA gradient hybridization technique.
abstract: Native DNA components in the human genome were identified with an improved RNA/DNA gradient hybridization technique. 3H-Labelled complementary RNA transcribed from total human DNA was hybridized to homologous DNA which had been mildly sheared to generate single-stranded ends. Unhybridized RNA was eliminated from the reaction mixture by column chromatography before the hybrids were subjected to CsCl gradient centrifugation. Nine radioactive peaks representing RNA/DNA hybrids were reproducibly found at buoyant densities of 1.687, 1.693, 1.696, 1.699, 1.702, 1.705, 1.708, 1.711 and 1.715 g/cm3. The technique was also utilized to hybridize I125-labelled human chromosomal RNA to DNA. Three distinct radioactive peaks were found at the heavy buoyant densities of 1.702, 1.705, and 1.708 g/cm3, suggesting a differential enrichment of DNA components with sequences complementary to chromosomal RNA.
mesh_terms: D001483:Base Sequence; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000032:analysis; D002875:Chromosomes / Q000032:analysis; D004247:DNA / Q000302:isolation & purification; D004277:DNA, Single-Stranded; D005260:Female; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009693:Nucleic Acid Hybridization; D010920:Placenta / Q000032:analysis*; D011247:Pregnancy; D012313:RNA / Q000302:isolation & purification; D014158:Transcription, Genetic
chemical_list: D004277:DNA, Single-Stranded; D012313:RNA; D004247:DNA