title: Accumulation of giant heterogeneous RNA molecules in acute myeloid leukemia blast cells.
abstract: Time course and "chase" experiments showed that, after incubation of acute myeloid leukemia blast cells with a labeled RNA precursor, a large proportion of radioactivity remained associated with RNA molecules larger than 45 S even after several hr. Double-labeling experiments with [5-3H]uridine and [methyl-14C]methionine indicated that unmethylated giant heterogeneous RNA larger than 45 S is processed much more slowly than the 45 S ribosomal precursor, so that relatively large amounts of fairly stable RNA of the former class accumulate in the cell. The measurement of labeled giant heterogeneous RNA molecules bound to polyuridylate-fiberglass filters showed that molecules carrying polyadenylate segments seemingly turn over faster than those lacking polyadenylate.
mesh_terms: D003609:Dactinomycin / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism; D008970:Molecular Weight; D011061:Poly A / Q000032:analysis / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism
chemical_list: D012334:RNA, Neoplasm; D012335:RNA, Ribosomal; D003609:Dactinomycin; D011061:Poly A