Gelfand, Robert and Attardi, Giuseppe (1981) Synthesis and Turnover of Mitochondrial Ribonucleic Acid in HeLa Cells: the Mature Ribosomal and Messenger Ribonucleic Acid Species Are Metabolically Unstable. Molecular and Cellular Biology, 1 (6). pp. 497-511. ISSN 0270-7306. http://resolver.caltech.edu/CaltechAUTHORS:20120717-154113041
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The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-^3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.
|Additional Information:||© 1981 American Society for Microbiology. Received 26 January 1981. Accepted 31 March 1981. These investigations were supported by Public Health Service grant GM-ll726 from the National Institutes of Health. We are very grateful to Eric Davidson for making the computer program used here available to us and for valuable advice and discussions. The technical assistance of Arger Drew and Benneta Keeley is gratefully acknowledged.|
|Official Citation:||Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable. R Gelfand and G Attardi Mol. Cell. Biol. June 1981 1:497-511; doi:10.1128/MCB.1.6.497|
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|Deposited By:||Ruth Sustaita|
|Deposited On:||18 Jul 2012 17:55|
|Last Modified:||18 Jul 2012 17:55|
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