英国剑桥大学Elliot Meyerowitz和Henrik Jönsson研究组合作取得最新进展。他们揭示了拟南芥中细胞分裂素激活细胞分裂的分子机制。该研究于2021年2月25日发表于国际一流学术期刊《科学》。

他们显示在拟南芥茎尖分生组织（SAM）中，细胞分裂素通过促进Myb结构域蛋白3R4（MYB3R4）的核穿梭来调节细胞分裂，MYB3R4是激活有丝分裂基因表达的转录因子。新合成的MYB3R4蛋白主要位于细胞质中。在G2 / M过渡期，MYB3R4的快速核积累（与细胞分裂素浓度的相关瞬时峰值一致）形成涉及importins的正反馈回路，并启动了驱动有丝分裂和胞质分裂的转录级联反应。改造的核限制MYB3R4可模拟细胞分裂素在增强细胞增殖和分生组织生长中的作用。

研究人员表示，有丝分裂原触发动物中的细胞分裂。在植物中，细胞分裂素是一组来自腺嘌呤的植物激素，可刺激细胞增殖。细胞分裂素信号转导由膜相关的组氨酸激酶受体启动，并通过磷酸化系统进行转导。

附：英文原文

Title: Molecular mechanism of cytokinin-activated cell division in Arabidopsis

Author: Weibing Yang, Sandra Cortijo, Niklas Korsbo, Pawel Roszak, Katharina Schiessl, Aram Gurzadyan, Raymond Wightman, Henrik Jnsson, Elliot Meyerowitz

Issue&Volume: 2021/02/25

Abstract: Mitogens trigger cell division in animals. In plants, cytokinins, a group of phytohormones derived from adenine, stimulate cell proliferation. Cytokinin signaling is initiated by membrane-associated histidine kinase receptors and transduced through a phosphorelay system. 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. Newly synthesized MYB3R4 protein resides predominantly in the cytoplasm. 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. An engineered nuclear-restricted MYB3R4 mimics the cytokinin effects in enhancement of cell proliferation and meristem growth.

DOI: 10.1126/science.abe2305

Source: https://science.sciencemag.org/content/early/2021/02/24/science.abe2305