title: Effects of Fcj1-Mos1 and mitochondrial division on aggregation of mitochondrial DNA nucleoids and organelle morphology.
abstract: Mitochondrial DNA (mtDNA) is packaged into DNA-protein complexes called nucleoids, which are distributed as many small foci in mitochondria. Nucleoids are crucial for the biogenesis and function of mtDNA. Here, using a yeast genetic screen for components that control nucleoid distribution and size, we identify Fcj1 and Mos1, two evolutionarily conserved mitochondrial proteins that maintain the connection between the cristae and boundary membranes. These two proteins are also important for establishing tubular morphology of mitochondria, as mitochondria lacking Fcj1 and Mos1 form lamellar sheets. We find that nucleoids aggregate, increase in size, and decrease in number in fcj1 and mos1 cells. In addition, Fcj1 form punctate structures and localized adjacent to nucleoids. Moreover, connecting mitochondria by deleting the DNM1 gene required for organelle division enhances aggregation of mtDNA nucleoids in fcj1 and mos1 cells, whereas single deletion of DNM1 does not affect nucleoids. Conversely, deleting F1Fo-ATP synthase dimerization factors generates concentric ring-like cristae, restores tubular mitochondrial morphology, and suppresses nucleoid aggregation in these mutants. Our findings suggest an unexpected role of Fcj1-Mos1 and organelle division in maintaining the distribution and size of mtDNA nucleoids.
authors.affiliation: Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Kie
authors.initials: K
authors.lastname: Itoh
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tamura
authors.forename: Miho
authors.initials: M
authors.lastname: Iijima
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sesaki
mesh_terms: D004272:DNA, Mitochondrial / Q000235:genetics*; D054629:Genome, Mitochondrial / Q000235:genetics; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D063154:Mitochondrial Dynamics; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: C503883:ATP20 protein, S cerevisiae; D004272:DNA, Mitochondrial; C542160:Fcj1 protein, S cerevisiae; D008164:Luminescent Proteins; C573102:MIC10 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D025261:Mitochondrial Proton-Translocating ATPases; C102550:TIM11 protein, S cerevisiae; D006180:Proton-Translocating ATPases