Functional analysis of a sensor kinase gene family implicated in cytokinin signaling in higher plants

高等植物中与细胞分裂素信号传导有关的传感器激酶基因家族的功能分析

• 批准号: 13640644
• 负责人: UEGUCHI Chiharu
• 金额: $ 2.24万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640644/
• 关键词: Cytokinin; Phytohormone; Sensor kinase; Signal Transduction; Shoot; シュート; 文化・成長

We identified a set of structurally related genes, AHK2 3 and 4, each encoding a sensor histidine kinase in Arabidopsis thaliana. We identified a loss-of-function mutation of the AHK4 gene. The mutant exhibited the cytokinin-resistant phenotype not only in inhibition of root growth by cytokinin but also in greening and shoot induction of calli. Moreover, AHK4 expressed in budding yeast showed histidine kinase activity in a manner dependent on the presence of cytokinin. These results strongly suggested that AHK4 is involved in the cytokinin-signaling pathway, as a direct receptor. We then screened and isolated loss-of function mutations of the AHK2 and 3 genes. Two independent alleles of ahk3 mutations exhibited the cytokinin-insensitive phenotype in greening and shoot induction of calli, indicating that AHK3 is also a cytokinin receptor. Although two independent alleles of ahk2 showed normal growth and cytokinin sensitivity, the ahk2/ 3 double mutant exhibited semi-dwarf phenotype in the above-ground tissues. These results suggest that AHK2 and 3 also function as cytokinin receptors and that cytokinins act as positive regulators in cell division activity in vivo.

我们确定了一组结构相关的基因，AHK 2 3和4，每个编码传感器组氨酸激酶在拟南芥。我们鉴定了AHK 4基因的功能缺失突变。该突变体不仅表现出细胞分裂素对根生长的抑制作用，而且在愈伤组织的绿化和芽诱导方面也表现出细胞分裂素抗性表型。此外，在芽殖酵母中表达的AHK 4显示组氨酸激酶活性的方式依赖于细胞分裂素的存在。这些结果有力地表明，AHK 4作为直接受体参与细胞分裂素信号通路。然后，我们筛选并分离AHK 2和3基因的功能丧失突变。AHK 3突变的两个独立等位基因在愈伤组织的绿化和芽诱导中表现出细胞分裂素不敏感的表型，表明AHK 3也是一种细胞分裂素受体。ahk 2的两个独立等位基因表现正常生长和细胞分裂素敏感性，而ahk 2/ 3双突变体在地上部表现半矮秆表型。这些结果表明，AHK 2和3也作为细胞分裂素受体的功能和细胞分裂素在体内细胞分裂活性中作为正调节剂。

项目成果

Ueguchi C., Koizumi H., Suzuki T., Mizuno T.: "Novel family of sensor histidine kinase genes in Arabidopsis thaliana"Plant & Cell Physiology. 42. 231-235 (2001)

Ueguchi C.、Koizumi H.、Suzuki T.、Mizuno T.：“拟南芥中传感器组氨酸激酶基因的新家族”植物

Ueguchi C., Koizumi H., Suzuki T.and Mizuno T.: "Novel family of sensor histidine kinase genes in Arabidopsis thaliana"Plant Cell Physiol. 42. 231-235 (2001)

Ueguchi C.、Koizumi H.、Suzuki T. 和 Mizuno T.：“拟南芥中传感器组氨酸激酶基因的新家族”植物细胞生理学。

Suzuki T., Sakurai K., Ueguchi C.and Mizuno T.: "Two types of putative nuclear factors that physically interact with histidine-containing phosphotransfer (HPt) domains, signaling mediators in His-to-Asp phosphorelay, in Arabidopsis thaliana"Plant Cell Phy

Suzuki T.、Sakurai K.、Ueguchi C. 和 Mizuno T.：“拟南芥中与含组氨酸磷酸转移 (HPt) 结构域、His-to-Asp 磷酸传递中的信号传导介质发生物理相互作用的两种推定核因子”

Izutsu, K., Wada, C., Komine, Y., Sako, T., Ueguchi, C., Nakura, S., and Wada, A.J.: "Escherichia coli ribosome-associated protein SRA, which increases during stationary phase"Bacteriol. 183. 2765-2773 (2001)

Izutsu, K.、Wada, C.、Komine, Y.、Sako, T.、Ueguchi, C.、Nakura, S. 和 Wada, A.J.：“大肠杆菌核糖体相关蛋白 SRA，在稳定期增加”

Suzuki T., Sakurai K., Ueguchi C., Mizuno T.: "Two types of putative nuclear factors that physically interact with histidine-containing phosphotransfer (HPt) domains, signaling mediators in His-to-Asp phosphorelay,in Arabidopsis thaliana"Plant & Cell Phys

Suzuki T.、Sakurai K.、Ueguchi C.、Mizuno T.：“拟南芥中与含组氨酸磷酸转移 (HPt) 结构域、His-to-Asp 磷酸传递中的信号传导介质发生物理相互作用的两种推定核因子”