Mitotic arrest caused by an X-ray microbeam in a single cell expressing EGFP-aurora kinase B.
Although the highest radiosensitivity of cells in the M phase among the other cell phases, such as the G(1), S and G(2) phases, has been known, the exact mechanism of radiosensitivity in mitotic cells remains unclear. Recently, mitotic arrest caused by DNA-damaging reagents has been shown, and the molecular mechanism in the arrest has been discussed in detail. In this study, abnormal cell-cycle progression in the M phase was investigated when a single mitotic cell in each mitotic stage was irradiated with a 5.35 keV X-ray microbeam focused on the cell nucleus. An X-ray microbeam irradiation system installed at BL-27 in Photon Factory, High Energy Accelerator Research Organization (HEARO, Tsukuba) was used. HeLa cells, genetically modified and expressing enhanced green fluorescent protein-tagged aurora kinase B, were used as irradiated samples in order to recognise the stage of each cell in the M phase. Thus, 10 Gy irradiation concentrated at the nucleus of a single cell elongated the cell-cycle progression in the M phase by delaying the metaphase/anaphase transition. The dose dependence of the elongation of the M phase was also examined. An irregular distribution of DNA in anaphase cells was observed after irradiation.
Tanno
Y
Y
Department of Physics, Graduate School of Natural Sciences, International Christian University, Mitaka, Tokyo 181-8585, Japan.
Kobayashi
K
K
Tatsuka
M
M
Gotoh
E
E
Takakura
K
K
D064107:Aurora Kinase B; D064127:Aurora Kinases; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008904:Miniaturization; D008938:Mitosis / Q000235:genetics* / Q000528:radiation effects*; D010315:Particle Accelerators / Q000295:instrumentation*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011829:Radiation Dosage; D011836:Radiation Tolerance / Q000528:radiation effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014965:X-Rays
D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C576921:AURKB protein, human; D064107:Aurora Kinase B; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases