title: Real-time observation of irradiated HeLa-cell modified by fluorescent ubiquitination-based cell-cycle indicator using synchrotron X-ray microbeam.
abstract: Fluorescent ubiquitination-based cell-cycle indicator (FUCCI) human cancer (HeLa) cells (red indicates G1; green, S/G2) were exposed to a synchrotron X-ray microbeam. Cells in either G1 or S/G2 were irradiated selectively according to their colour in the same microscopic field. Time-lapse micrographs of the irradiated cells were acquired for 24 h after irradiation. For fluorescent immunostaining, phosphorylated histone proteins (γ-H2AX) indicated the induction of DNA double-strand breaks. The cell cycle was arrested by irradiation at S/G2. In contrast, cells irradiated at G1 progressed to S/G2. The foci were induced in cells irradiated at both G1 and S/G2, suggesting that the G1-S (or S) checkpoint pathway does not function in HeLa cells due to the fact that the cells are functionally p53 deficient, even though X-ray microbeam irradiation significantly induces double-strand breaks. These results demonstrate that single FUCCI cell exposure and live cell imaging are powerful methods for studying the effects of radiation on the cell cycle.
authors: Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan.
authors: A
authors: A
authors: Narita
authors: Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors: K
authors: K
authors: Kaminaga
authors: Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan yokoya.akinari@jaea.go.jp.
authors: A
authors: A
authors: Yokoya
authors: Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan.
authors: M
authors: M
authors: Noguchi
authors: Photon Factory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
authors: K
authors: K
authors: Kobayashi
authors: Photon Factory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
authors: N
authors: N
authors: Usami
authors: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors: K
authors: K
authors: Fujii
mesh_terms: D002453:Cell Cycle / Q000528:radiation effects*; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D005456:Fluorescent Dyes / Q000032:analysis*; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000528:radiation effects*; D010766:Phosphorylation / Q000528:radiation effects; D017356:Synchrotrons; D054875:Ubiquitination / Q000528:radiation effects*; D014965:X-Rays
chemical_list: D005456:Fluorescent Dyes