Reisen Daniel, Leborgne-Castel Nathalie, Ozalp Cengiz, Chaumont François, Marty Francis
Laboratoire de phytoBiologie Cellulaire, UPR.ES 469, BP 47870, Université de Bourgogne, 21078 Dijon Cedex, France.
Plant Mol Biol. 2003 May;52(2):387-400. doi: 10.1023/a:1023961332391.
In plants, vacuoles are essential organelles that undergo dynamic volume changes during cell growth due to rapid and high flow of water through tonoplast water-carrying channels composed of integral proteins (tonoplast aquaporins). The tonoplast BobTIP26-1 from cauliflower has previously been shown to be an efficient active aquaporin in Xenopus leavis oocytes. In this study we used tobacco (Nicotiana tabacum cv. Wisconsin 38) suspension cells to examine the effect of BobTIP26-1 expression. In order to follow the intracellular localisation of the protein in real time, the gfp sequence was fused downstream to the BobTIP26-1 coding region. The fusion protein BobTIP26-1::GFP is less active than BobTIP26-1 by itself when expressed in Xenopus oocytes. Nevertheless, this fusion protein is well targeted to the tonoplast of the plant suspension cell when expressed via Agrobacterium co-cultivation. A complex tonoplast labelling is shown when young vacuolated cells are observed. The expression of the fusion protein does not affect the growth rate of the cells but increases their volume. We postulate that the increase in cell volume is triggered by the fusion protein allowing vacuolar volume increase.
在植物中，液泡是重要的细胞器，在细胞生长过程中，由于水通过由整合蛋白（液泡膜水通道蛋白）组成的液泡膜水运输通道快速大量流动，液泡会经历动态的体积变化。此前已证明，来自花椰菜的液泡膜BobTIP26-1在非洲爪蟾卵母细胞中是一种高效的活性水通道蛋白。在本研究中，我们使用烟草（Nicotiana tabacum cv. Wisconsin 38）悬浮细胞来检测BobTIP26-1表达的影响。为了实时追踪该蛋白在细胞内的定位，将绿色荧光蛋白（gfp）序列融合到BobTIP26-1编码区的下游。当在非洲爪蟾卵母细胞中表达时，融合蛋白BobTIP26-1::GFP的活性低于单独的BobTIP26-1。然而，通过农杆菌共培养表达时，这种融合蛋白能很好地定位到植物悬浮细胞的液泡膜上。观察年轻的液泡化细胞时，会出现复杂的液泡膜标记。融合蛋白的表达不影响细胞的生长速率，但会增加细胞体积。我们推测，细胞体积的增加是由融合蛋白引发液泡体积增加所致。
