title: Mitochondrial dynamics controlled by mitofusins define organelle positioning and movement during mouse oocyte maturation.
abstract: Mitochondria are abundant in fully grown mammalian oocytes with a unique spherical morphology, but the mechanisms controlling mitochondria behavior are not well understood. Here we describe for the first time the control of mitochondrial behavior in mouse oocytes by a fusion/fission mechanism. Mitofusins (Mfn1 and Mfn2) and OPA1 proteins are required for outer and inner mitochondrial membrane fusion, respectively, whereas Drp1 is the key regulator of mitochondrial fission. We show that mouse oocytes express the Mfn1, Mfn2, Opa1 and Drp1 proteins, both in immature and mature oocytes at similar levels. Overexpression of Mfn1 or Mfn2 causes marked mitochondrial aggregation, particularly in the perinuclear region during meiotic progression. Tracking of mitochondria with chromosomes or endoplasmic reticulum (ER) throughout oocyte maturation demonstrates that Mfn1 and Mfn2-promoted mitochondrial aggregation disturbs the spatiotemporal dynamic of the chromosomes and ER, respectively. Our findings suggest that organelle dynamics are co-ordinately controlled during meiotic division, and an imbalance of mitochondrial fusion/fission leads to disorganization of the organelle compartments.
authors.affiliation: Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Wakai
authors.affiliation: Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan.
authors.forename: Yuichirou
authors.initials: Y
authors.lastname: Harada
authors.affiliation: Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Miyado
authors.affiliation: Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan tomohiro@nodai.ac.jp.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kono
mesh_terms: D000818:Animals; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008561:Membrane Fusion; D051379:Mice; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D063154:Mitochondrial Dynamics / Q000235:genetics*; D051336:Mitochondrial Membranes / Q000378:metabolism; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D020558:GTP Phosphohydrolases; C488750:Mfn1 protein, mouse; C488751:Mfn2 protein, mouse; C498809:Opa1 protein, mouse
keywords: endoplasmic reticulum; meiosis; mitochondrial dynamics; oocyte maturation; spindle formation