title: Live-cell imaging study of mitochondrial morphology in mammalian cells exposed to X-rays.
abstract: Morphological changes in mitochondria induced by X-irradiation in normal murine mammary gland cells were studied with a live-cell microscopic imaging technique. Mitochondria were visualised by staining with a specific fluorescent probe in the cells, which express fluorescent ubiquitination-based cell-cycle indicator 2 (Fucci2) probes to visualise cell cycle. In unirradiated cells, the number of cells with fragmented mitochondria was about 20 % of the total cells through observation period (96 h). In irradiated cells, the population with fragmented mitochondria significantly increased depending on the absorbed dose. Particularly, for 8 Gy irradiation, the accumulation of fragmentation persists even in the cells whose cell cycle came to a stand (80 % in G1 (G0-like) phase). The fraction reached to a maximum at 96 h after irradiation. The kinetics of the fraction with fragmented mitochondria was similar to that for cells in S/G2/M phase (20 %) through the observation period (120 h). The evidences show that, in irradiated cells, some signals are continually released from a nucleus or cytoplasm even in the G0-like cells to operate some sort of protein machineries involved in mitochondrial fission. It is inferred that this delayed mitochondrial fragmentation is strongly related to their dysfunction, and hence might modulate radiobiological effects such as mutation or cell death.
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan noguchi.miho@jaea.go.jp.
authors.forename: M
authors.initials: M
authors.lastname: Noguchi
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kanari
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yokoya
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Narita
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fujii
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000528:radiation effects*; D002478:Cells, Cultured; D005260:Female; D005456:Fluorescent Dyes / Q000032:analysis*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008321:Mammary Glands, Animal / Q000528:radiation effects*; D051379:Mice; D008928:Mitochondria / Q000502:physiology* / Q000528:radiation effects*; D008938:Mitosis / Q000528:radiation effects*; D054875:Ubiquitination / Q000528:radiation effects; D014965:X-Rays
chemical_list: D005456:Fluorescent Dyes