Open AccessEarly termination of heterogeneous nuclear RNA transcripts in mammalian cells: accentuation by 5,6-dichloro 1-beta-D-ribofuranosylbenzimidazole.
Author(s) -
Igor Tamm,
Toyoko Kikuchi
Publication year - 1979
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.76.11.5750
Subject(s) - precursor mrna , rna , transcription (linguistics) , microbiology and biotechnology , biology , cell nucleus , messenger rna , elongation , rna polymerase ii , biochemistry , nucleus , gene expression , rna splicing , gene , promoter , linguistics , philosophy , materials science , ultimate tensile strength , metallurgy
Labeling of RNA in isolated HeLa cell nuclei in vitro reveals an abundance of short RNA chains made by RNA polymerase II. These short chains were initiated prior to isolation of the nuclei. The short abundant chains are increased in amount in nuclei isolated from cells treated with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). Kinetic evidence indicates that the bulk of the putative heterogeneous nuclear RNA (hnRNA) precursor molecules that are terminated early in vivo are terminated approximately 100-300 nucleotides from sites of initiation. DRB increases the frequency of early termination, but there is a fraction of hnRNA precursor molecules whose elongation is not affected by DRB. Heparin is useful in studies of hnRNA transcription in isolated nuclei because it enhances chain elongation.