Symmetrical in vivo transcription of mitochondrial DNA in HeLa cells.
RNA.DNA hybridization experiments utilizing separated strands of HeLa mitochondrial DNA and mit-RNA from HeLa cells exposed to short pulses of [5-(3)H]uridine have shown that the labeled RNA hybridizes with both the light (L) and the heavy (H) strand, though to a different relative extent depending upon the labeling time. Thus, hybridization of pulse-labeled RNA is about equal with the two strands when the pulse is very short (1-5 min), and becomes more and more predominant with the H strand with increasing pulse length. Pulse-labeled fast-sedimenting mit-RNA forms RNase-resistant double-stranded structures up to more than 5 mum long when self-annealed or annealed with an excess of unlabeled mit-RNA. These observations and the previous evidence of complete transcription of the H strand strongly suggest that mit-DNA is transcribed in HeLa cells symmetrically over a considerable portion of its length, with the transcript of the L strand being rapidly degraded or otherwise removed from the mitochondrial fraction.
D001345:Autoradiography; D002499:Centrifugation, Density Gradient; D004273:DNA, Neoplasm / Q000032:analysis / Q000096:biosynthesis*; D003609:Dactinomycin / Q000494:pharmacology; D005815:Genetic Code; D006367:HeLa Cells / Q000378:metabolism*; D006801:Humans; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D012334:RNA, Neoplasm / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism; D012260:Ribonucleases / Q000494:pharmacology; D014316:Tritium; D014529:Uridine / Q000378:metabolism
D004273:DNA, Neoplasm; D012334:RNA, Neoplasm; D014316:Tritium; D003609:Dactinomycin; D012260:Ribonucleases; D014529:Uridine