Organ specificity of a vacuolar Ca2 +-binding protein RVCaB in radish and its expression under Ca2 +-deficient conditions
Organ specificity of a vacuolar Ca2 +-binding protein RVCaB in radish and its expression under Ca2 +-deficient conditions
复制标题
萝卜液泡Ca2+结合蛋白RVCaB的器官特异性及其在Ca2+缺乏条件下的表达
作者：
K. Yuasa;M. Maeshima
萝卜液泡中含有一种新型的钙结合蛋白(RVCaB)，它对钙离子具有高亲和力和低亲和力。该蛋白能够刺激细胞内的钙离子进入液泡，这是由钙-ATPase和钙/氢逆向转运蛋白共同驱动的。本研究发现，RVCaB在幼苗下胚轴和成熟主根中的表达水平较高，而在幼根和成熟叶片中的表达水平较低。RVCaB蛋白在下胚轴和主根中含量丰富，而在叶片中缺失。RVCaB在主根中的转录水平和蛋白水平在主根成熟过程中逐渐升高。幼苗下胚轴中RVCaB基因的表达水平在从10 mM CaCl2到水的几个小时内翻了一番，但在100 mM CaCl2中该水平受到强烈抑制。RVCaB基因对Ca~(2+)的这种反应是特异的，不与K~+和Mg~(2+)等其他离子发生反应。讨论了RVCaB在主根液泡中作为钙离子隔离蛋白的作用，以弥补钙缺乏。
Radish vacuoles contain a new type of Ca2+-binding protein (RVCaB) with high capacity and low affinity for Ca2+. The protein is able to stimulate Ca2+ uptake into vacuoles, which is driven by Ca2+-ATPase and Ca2+/H+ antiporter. In the present study, we found that the level of RVCaB mRNA is high in seedling hypocotyls and mature taproots but low in young roots and mature leaves. The RVCaB protein was abundant in hypocotyls and taproots but absent in leaves. The levels of the transcript and protein of RVCaB in taproots were gradually increased during maturation. The level of RVCaB mRNA in seedling hypocotyls doubled within a few hours when the growth medium was changed from 10 mM CaCl2 to water, although the level was strongly suppressed in 100 mM CaCl2. This response of the RVCaB gene was specific to Ca2+ and did not occur with other ions including K+ and Mg2+. RVCaB functioning as a Ca2+-sequestering protein in taproot vacuoles to provide for the Ca2+ deficiency is discussed.
影响因子：
3.5
作者：
Shigaki, T;Hirschi, K
通讯作者：
Hirschi, K