title: Transcription of mammalian messenger RNAs by a nuclear RNA polymerase of mitochondrial origin.
abstract: Transcription of eukaryotic genes is performed by three nuclear RNA polymerases, of which RNA polymerase II is thought to be solely responsible for the synthesis of messenger RNAs. Here we show that transcription of some mRNAs in humans and rodents is mediated by a previously unknown single-polypeptide nuclear RNA polymerase (spRNAP-IV). spRNAP-IV is expressed from an alternative transcript of the mitochondrial RNA polymerase gene (POLRMT). The spRNAP-IV lacks 262 amino-terminal amino acids of mitochondrial RNA polymerase, including the mitochondrial-targeting signal, and localizes to the nucleus. Transcription by spRNAP-IV is resistant to the RNA polymease II inhibitor alpha-amanitin but is sensitive to short interfering RNA specific for the POLRMT gene. The promoters for spRNAP-IV differ substantially from those used by RNA polymerase II, do not respond to transcriptional enhancers and contain a common functional sequence motif.
authors.affiliation: Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: Julia E
authors.initials: JE
authors.lastname: Kravchenko
authors.forename: Igor B
authors.initials: IB
authors.lastname: Rogozin
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Koonin
authors.forename: Peter M
authors.initials: PM
authors.lastname: Chumakov
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics; D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000201:enzymology*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D021381:Protein Transport; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D051381:Rats; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D000444:Aldehyde Dehydrogenase; D012321:DNA-Directed RNA Polymerases