Evidence for the existence of several molecular species in the "45S fraction" of mammalian ribosomal precursor RNA.
Analysis of RNA (after 5 or 60 min of labeling with [(3)H]uridine) from L5178Y cells by electrophoresis in 1.7% polyacrylamide gels demonstrates that the ribosomal RNA "45S fraction" is not homogeneous but consists of at least three molecular species, conventionally designated 47S RNA, 46S RNA, and 45S RNA. Alternatives to the classical scheme for the biosynthesis of ribosomal RNA in mammalian cells are discussed.
D001345:Autoradiography; D002247:Carbon Isotopes; D002478:Cells, Cultured / Q000032:analysis / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D004589:Electrophoresis, Disc; D006367:HeLa Cells / Q000032:analysis; D008970:Molecular Weight; D012335:RNA, Ribosomal / Q000032:analysis* / Q000096:biosynthesis; D014316:Tritium; D014529:Uridine / Q000378:metabolism
D002247:Carbon Isotopes; D012335:RNA, Ribosomal; D014316:Tritium; D003609:Dactinomycin; D014529:Uridine