title: Negative regulation of mitochondrial transcription by mitochondrial topoisomerase I.
abstract: Mitochondrial topoisomerase I is a genetically distinct mitochondria-dedicated enzyme with a crucial but so far unknown role in the homeostasis of mitochondrial DNA metabolism. Here, we present data suggesting a negative regulatory function in mitochondrial transcription or transcript stability. Deficiency or depletion of mitochondrial topoisomerase I increased mitochondrial transcripts, whereas overexpression lowered mitochondrial transcripts, depleted respiratory complexes I, III and IV, decreased cell respiration and raised superoxide levels. Acute depletion of mitochondrial topoisomerase I triggered neither a nuclear mito-biogenic stress response nor compensatory topoisomerase IIβ upregulation, suggesting the concomitant increase in mitochondrial transcripts was due to release of a local inhibitory effect. Mitochondrial topoisomerase I was co-immunoprecipitated with mitochondrial RNA polymerase. It selectively accumulated and rapidly exchanged at a subset of nucleoids distinguished by the presence of newly synthesized RNA and/or mitochondrial RNA polymerase. The inactive Y559F-mutant behaved similarly without affecting mitochondrial transcripts. In conclusion, mitochondrial topoisomerase I dampens mitochondrial transcription and thereby alters respiratory capacity. The mechanism involves selective association of the active enzyme with transcriptionally active nucleoids and a direct interaction with mitochondrial RNA polymerase. The inhibitory role of topoisomerase I in mitochondrial transcription is strikingly different from the stimulatory role of topoisomerase I in nuclear transcription.
authors: Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Med. Faculty, D-40225 Düsseldorf, Germany, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA, Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, University of Köln, D-50931 Köln, Germany, Center for Molecular Medicine Cologne, University of Köln, D-50931 Köln, Germany, Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases, University of Köln, D-50931 Köln, Germany, Department of Pediatrics, Med. Faculty, University of Köln, D-50931 Köln, Germany and Center for Microbiology and Virology, Institute of Virology, Heinrich-Heine-University, Med. Faculty, D-40225 Düsseldorf, Germany.
authors: Stefan
authors: S
authors: Sobek
authors: Ilaria
authors: I
authors: Dalla Rosa
authors: Yves
authors: Y
authors: Pommier
authors: Beatrice
authors: B
authors: Bornholz
authors: Faiza
authors: F
authors: Kalfalah
authors: Hongliang
authors: H
authors: Zhang
authors: Rudolf J
authors: RJ
authors: Wiesner
authors: Jürgen-Christoph
authors: JC
authors: von Kleist-Retzow
authors: Frank
authors: F
authors: Hillebrand
authors: Heiner
authors: H
authors: Schaal
authors: Christian
authors: C
authors: Mielke
authors: Morten O
authors: MO
authors: Christensen
authors: Fritz
authors: F
authors: Boege
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D000077278:RNA, Mitochondrial; D014158:Transcription, Genetic
chemical_list: D000077278:RNA, Mitochondrial; D012313:RNA; D004264:DNA Topoisomerases, Type I
references: Eur J Biochem. 2003 Oct;270(20):4173-86
references: 14519130
references: Mol Biol Cell. 2003 Apr;14(4):1583-96
references: 12686611
references: Proc Natl Acad Sci U S A. 2003 Jun 10;100(12):7123-8
references: 12773624
references: Proc Natl Acad Sci U S A. 2011 Aug 16;108(33):13534-9
references: 21808029
references: Mol Cell Biol. 1987 Dec;7(12):4308-16
references: 2449604
references: Cell. 2007 Jul 27;130(2):273-85
references: 17662942
references: J Virol. 2013 Mar;87(5):2707-20
references: 23255806
references: J Mol Biol. 2008 Sep 5;381(3):540-9
references: 18588899
references: Nucleic Acids Res. 2004 Nov 16;32(20):6015-27
references: 15547250
references: Nucleic Acids Res. 2004 Apr 19;32(7):2087-92
references: 15096574
references: PLoS One. 2012;7(7):e41094
references: 22911747
references: Nat Genet. 2002 Jul;31(3):289-94
references: 12068295
references: Nucleic Acids Res. 2009 Oct;37(19):6414-28
references: 19720733
references: PLoS One. 2011;6(7):e22583
references: 21799907
references: Proc Natl Acad Sci U S A. 2002 Sep 17;99(19):12114-9
references: 12209014
references: Proc Natl Acad Sci U S A. 2010 Jul 6;107(27):12133-8
references: 20562347
references: Nat Rev Mol Cell Biol. 2002 Jun;3(6):430-40
references: 12042765
references: Biochemistry. 2008 Oct 28;47(43):11196-203
references: 18826252
references: Chromosoma. 2005 Jul;114(2):75-85
references: 15830206
references: Biochem Biophys Res Commun. 2007 Jun 22;358(1):203-8
references: 17475217
references: Methods Mol Biol. 2006;326:9-16
references: 16780191
references: Nature. 1993 Sep 16;365(6443):227-32
references: 8396729
references: Proc Natl Acad Sci U S A. 1988 Feb;85(4):1060-4
references: 2829214
references: Mitochondrion. 2007 Sep;7(5):311-21
references: 17698423
references: Genes Dev. 1997 Feb 1;11(3):397-407
references: 9030691
references: Chromosoma. 1988;96(6):411-6
references: 2851418
references: Annu Rev Biochem. 2007;76:679-99
references: 17408359
references: Clin Chim Acta. 1994 Jul;228(1):35-51
references: 7955428
references: Biochim Biophys Acta. 2009 May;1787(5):303-11
references: 19366610
references: Nat Cell Biol. 2009 Nov;11(11):1315-24
references: 19838172
references: Proc Natl Acad Sci U S A. 1993 Dec 15;90(24):11508-12
references: 8265582
references: Nat Struct Mol Biol. 2011 Nov 04;18(11):1179-81
references: 22056802
references: J Cell Physiol. 2006 Dec;209(3):923-34
references: 16972274
references: Mol Biol Cell. 2007 Sep;18(9):3225-36
references: 17581862
references: J Biol Chem. 2002 Sep 27;277(39):35932-8
references: 12119295
references: EMBO Rep. 2009 Aug;10(8):887-93
references: 19557000
references: Nucleic Acids Res. 2011 Aug;39(15):6620-32
references: 21531700
references: Mol Cell Biol. 1998 Jul;18(7):4358-67
references: 9632819
references: Proc Natl Acad Sci U S A. 2001 Sep 11;98(19):10608-13
references: 11526219
references: Cell. 2012 Mar 16;148(6):1145-59
references: 22424226
references: J Biol Chem. 2006 Sep 1;281(35):25791-802
references: 16825194
references: J Cell Biol. 2008 Jun 30;181(7):1117-28
references: 18573913
references: J Biol Chem. 2008 Feb 8;283(6):3665-3675
references: 18063578
references: BMC Biol. 2004 May 24;2:9
references: 15157274