UV-B辐射对拟南芥细胞周期G1/S期转变的影响

以同步化的拟南芥（Arabidopsis thaliana）根尖细胞为材料，研究了UV-B辐射对拟南芥细胞周期G1／S期转变的影响。细胞周期荧光显微图像分析表明，UV-B辐射延缓了拟南芥根尖细胞G1／S期的转变。基因表达的RT-PCR检测表明，在UV-B辐射下G1／S期转变的标志基因HistoneH4和E2Fa的表达受抑制，而G1／S期转变的抑制因子KRP2基因表达则受诱导上调。单细胞凝胶电泳检测结果表明，UV-B辐射引起拟南芥根尖细胞内积累大量的环丁烷嘧啶二聚体。以上结果表明，UV-B辐射抑制植物的生长可能受细胞周期和DNA损伤调控。

UV-B Induced GI/S Arrest in Arabidopsis Root Tips

Cell cycle regulation is closely linked to plant growth and development. The plant cell cycle responds rapidly to stimuli from both the internal and external environment. We present a model of partially synchronized root tips of Arabidopsis to study the effects of UV-B radiation on the G1/S transition in the cell cycle. Analysis of the fluorescence image under microscopy indicated that G1/S arrest was induced by UV-B radiation. The expression of two factors of GI/S transition, Histone H4 and E2Fa, was repressed under UV-B radiation, whereas the negative factor of G1/S transition, KRP2, was upregulated by UV-B radiation. UV-B radiation during the cell cycle induced accumulation of cyclobutane pyrimidine dimers. All these results suggested that UV-B- induced plant growth inhibition may be mediated by cell cycle regulation and DNA damage.