主要发现：Here we show, in the Arabidopsis shoot apical meristem (SAM), that cytokinin regulates cell division by promoting nuclear shuttling of Myb-domain protein 3R4 (MYB3R4), a transcription factor that activates mitotic gene expression. 

结果1-新合成的MYB3R4：Newly synthesized MYB3R4 protein resides predominantly in the cytoplasm. 

结果2-MYB3R4的核质穿梭：At the G2/M transition, rapid nuclear accumulation of MYB3R4—consistent with an associated transient peak in cytokinin concentration—feeds a positive-feedback loop involving importins, and initiates a transcriptional cascade that drives mitosis and cytokinesis. 

结果3-编辑MYB3R4：An engineered nuclear-restricted MYB3R4 mimics the cytokinin effects in enhancement of cell proliferation and meristem growth.

 摘 要