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Updated: Jul 18, 2026
Real-Time Monitoring of Aurora kinase A Activation using Conformational FRET Biosensors in Live Cells
Published on: July 30, 2020
Mitotic arrest caused by an X-ray microbeam in a single cell expressing EGFP-aurora kinase B
Y Tanno1, K Kobayashi, M Tatsuka
1Department of Physics, Graduate School of Natural Sciences, International Christian University, Mitaka, Tokyo 181-8585, Japan.
Abstract:
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.
Insights
Irradiating a single cell nucleus with X-rays delays the M phase cell cycle progression, specifically the metaphase/anaphase transition. This study investigates the radiosensitivity mechanisms in mitotic cells, revealing DNA distribution abnormalities post-irradiation.
Area of Science:
- Cell Biology
- Radiation Biology
- Molecular Biology
Background:
- The M phase exhibits the highest radiosensitivity among cell cycle phases, but the precise mechanisms remain unclear.
- DNA-damaging agents can induce mitotic arrest, with detailed molecular mechanisms being investigated.
Purpose of the Study:
- To investigate abnormal cell-cycle progression in the M phase following targeted X-ray microbeam irradiation of individual mitotic cells.
- To elucidate the effects of nuclear irradiation on mitotic stage transitions and DNA distribution.
Main Methods:
- Utilized a 5.35 keV X-ray microbeam system at the Photon Factory.
- Employed HeLa cells genetically modified to express enhanced green fluorescent protein-tagged aurora kinase B for precise M phase staging.
- Irradiated single mitotic cells at the nuclear level with 10 Gy X-rays.
Main Results:
- Nuclear X-ray irradiation (10 Gy) significantly elongated M phase progression by delaying the metaphase/anaphase transition.
- Observed dose-dependent effects on M phase duration.
- Detected irregular DNA distribution in anaphase cells subsequent to irradiation.
Conclusions:
- Targeted nuclear irradiation disrupts normal mitotic progression, specifically impacting the metaphase/anaphase transition.
- The findings contribute to understanding the radiosensitivity of mitotic cells and the consequences of DNA damage during mitosis.
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