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>Persistent synthesis of 5S RNA when production of 28S and 18S ribosomal RNA is inhibited by low doses of actinomycin D
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Persistent synthesis of 5S RNA when production of 28S and 18S ribosomal RNA is inhibited by low doses of actinomycin D
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机译：Persistent synthesis of 5S RNA when production of 28S and 18S ribosomal RNA is inhibited by low doses of actinomycin D
AbstractTo determine whether transcription of the genes coding for 5S ribosomal RNA depends upon the concurrent activity of the genes for 28S and 18S ribosomal RNA we studied the synthesis of 5S RNA in cultured L cells when the synthesis of the 45S precursor of 28 and 18S RNA was inhibited with low doses of actinomycin D. Synthesis of 5S RNA was measured by following the incorporation of3H uridine into components which, upon acrylamide gel electrophoresis, co‐migrated with markers of 5S RNA obtained from32P labeled ribosomes. We observed that the synthesis of 5S RNA persists in the absence of detectable 28S and 18S RNA synthesis, continuing at the normal rate for several hours and at a reduced rate for at least a generation time. This strongly supports the concept that 45S RNA is not a precursor of 5S RNA, and indicates furthermore that neither the 45S component, nor any of the intermediates involved in its transition to 28S and 18S RNA, are involved in controlling the output of the 5S genes The 5S RNA which is made during actinomycin treatment is retained predominantly in the nucleoplasm and undergoes a turnover of about 3.5 per hour. It apparently cannot be utilized when ribosome synthesis resumes following removal of the actinomyci
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