Antosiewicz D M, Polisensky D H, Braam J
Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251-1892, USA.
Plant J. 1995 Nov;8(5):623-36. doi: 10.1046/j.1365-313x.1995.08050623.x.
TCH3 is an Arabidopsis touch (TCH) gene isolated as a result of its strong and rapid upregulation in response to mechanical stimuli, such as touch and wind. TCH3 encodes an unusual calcium ion-binding protein that is closely related to calmodulin but has the potential to bind six calcium ions. Here it is shown that TCH3 shows a restricted pattern of accumulation during Arabidopsis vegetative development. These data provide insight into the endogenous signals that may regulate TCH3 expression and the sites of TCH3 action. TCH3 is abundant in the shoot apical meristem, vascular tissue, the root columella and pericycle cells that give rise to lateral roots. In addition, TCH3 accumulation in cells of developing shoots and roots closely correlates with the process of cellular expansion. Following wind stimulation, TCH3 becomes more abundant in specific regions including the branchpoints of leaf primordia and stipules, pith parenchyma, and the vascular tissue. The consequences of TCH3 upregulation by wind are therefore spatially restricted and TCH3 may function at these sites to modify cell or tissue characteristics following mechanical stimulation. Because TCH3 accumulates specifically in cells and tissues that are thought to be under the influence of auxin, auxin levels may regulate TCH3 expression during development. TCH3 is upregulated in response to low levels of exogenous indole-3-acetic acid (IAA), but not by inactive auxin-related compounds. These results suggest that TCH3 protein may play roles in mediating physiological responses to auxin and mechanical environmental stimuli.
TCH3是一种拟南芥触摸（TCH）基因，它是由于在响应机械刺激（如触摸和风）时强烈且快速上调而被分离出来的。TCH3编码一种不寻常的钙离子结合蛋白，该蛋白与钙调蛋白密切相关，但有结合六个钙离子的潜力。本文表明，TCH3在拟南芥营养发育过程中呈现出受限的积累模式。这些数据为可能调节TCH3表达的内源性信号以及TCH3的作用位点提供了见解。TCH3在茎尖分生组织、维管组织、根柱细胞和产生侧根的中柱鞘细胞中含量丰富。此外，TCH3在发育中的茎和根细胞中的积累与细胞扩张过程密切相关。风刺激后，TCH3在包括叶原基和托叶的分支点、髓薄壁组织和维管组织等特定区域变得更加丰富。因此，风上调TCH3的后果在空间上是受限的，TCH3可能在这些位点发挥作用，以在机械刺激后改变细胞或组织特征。由于TCH3特异性地在被认为受生长素影响的细胞和组织中积累，生长素水平可能在发育过程中调节TCH3的表达。TCH3对外源吲哚-3-乙酸（IAA）的低水平有上调反应，但对无活性的生长素相关化合物没有反应。这些结果表明，TCH3蛋白可能在介导对生长素和机械环境刺激的生理反应中发挥作用。
