title: mtDNA makes a U-turn for the mitochondrial nucleoid.
abstract: Mitochondria contain mtDNA derived from the ancestral endosymbiont genome. Important subunits of the oxidative phosphorylation system, which supplies cells with the energy currency ATP, are encoded by mtDNA. A naked mtDNA molecule is longer than a typical mitochondrion and is therefore compacted in vivo to form a nucleoprotein complex, denoted the mitochondrial nucleoid. Mitochondrial transcription factor A (TFAM) is the main factor packaging mtDNA into nucleoids and is also essential for mtDNA transcription initiation. The crystal structure of TFAM shows that it bends mtDNA in a sharp U-turn, which likely provides the structural basis for its dual functions. Super-resolution imaging studies have revealed that the nucleoid has an average diameter of ∼100nm and frequently contains a single copy of mtDNA. In this review the structure of the mitochondrial nucleoid and its possible regulatory roles in mtDNA expression will be discussed.
authors.affiliation: Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kukat
authors.forename: Nils-Göran
authors.initials: NG
authors.lastname: Larsson
mesh_terms: D000255:Adenosine Triphosphate / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004272:DNA, Mitochondrial / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D005786:Gene Expression Regulation; D008928:Mitochondria / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000737:chemistry*; D010085:Oxidative Phosphorylation; D011487:Protein Conformation; D014157:Transcription Factors / Q000737:chemistry*; D061785:Transcription Initiation, Genetic
chemical_list: D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; C499631:TFAM protein, human; D014157:Transcription Factors; D000255:Adenosine Triphosphate
keywords: TFAM; mitochondrial nucleoid; mtDNA