Aoyama Takashi, Oka Atsuhiro
Laboratory of Molecular Biology, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
J Plant Res. 2003 Jun;116(3):221-31. doi: 10.1007/s10265-003-0094-6. Epub 2003 Apr 17.
Cytokinins regulate various events in plant development according to the intrinsic developmental program and in response to environmental stimuli. Recent genetic and molecular biological studies have revealed the framework of the intracellular signal transduction pathway from cytokinin perception to transcriptional regulation of primary cytokinin-responsive genes in Arabidopsis thaliana. Membrane-bound histidine kinases, including CRE1/AHK4, AHK2, and AHK3, perceive cytokinins. The signal is then transferred via histidine-containing phosphotransfer factors, AHPs, to transcription-factor-type response regulators, such as ARR1, which execute the signal-dependent transactivation of primary cytokinin-responsive genes, including those for other types of response regulator. Simply stated, the cytokinin signal is mediated by the His-Asp phosphorelay, which was originally found in bacterial two-component regulatory systems. However, many details, especially those that are essential for elucidating the regulatory mechanisms underlying complicated cytokinin responses, remain unknown.
细胞分裂素根据内在发育程序并响应环境刺激，调控植物发育中的各种事件。最近的遗传学和分子生物学研究揭示了拟南芥中从细胞分裂素感知到初级细胞分裂素响应基因转录调控的细胞内信号转导途径框架。包括CRE1/AHK4、AHK2和AHK3在内的膜结合组氨酸激酶感知细胞分裂素。然后信号通过含组氨酸的磷酸转移因子AHPs传递给转录因子型响应调节因子，如ARR1，后者对包括其他类型响应调节因子基因在内的初级细胞分裂素响应基因进行信号依赖性反式激活。简而言之，细胞分裂素信号由最初在细菌双组分调节系统中发现的His-Asp磷酰基转移介导。然而，许多细节，尤其是那些对于阐明复杂细胞分裂素反应背后调控机制至关重要的细节，仍然未知。
