A proline-, threonine-, and glycine-rich protein down-regulated by drought is localized in the cell wall of xylem elements
A proline-, threonine-, and glycine-rich protein down-regulated by drought is localized in the cell wall of xylem elements
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DOI：
10.1104/pp.121.2.557
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发表时间：
1999-10-01
期刊：
影响因子：
7.4
通讯作者：
Tabaeizadeh, Z
中科院分区：
文献类型：
--
作者：
Harrak, H;Chamberland, H;Tabaeizadeh, Z
李立新，王晓明，王晓明，等。野生番茄中脯氨酸、苏氨酸和甘氨酸丰富蛋白（PTGRP）的克隆[j] .中国番茄学报[1996]39:1181 -1193。Northern-blot分析和原位杂交研究表明，PTGRP在干旱胁迫下下调。干旱胁迫8 d植株叶片和茎中mRNA水平较正常浇水植株降低5 ~ 10倍。当干旱胁迫的植物重新浇水时，mRNA重新积累。针对谷胱甘肽s -转移酶/PTGRP融合蛋白的抗体通过免疫金标记来阐明该蛋白的亚细胞定位。在定期浇水的赤ense植物中，PTGRP蛋白定位于木质部坑膜和崩解的初生壁。对干旱胁迫植物的切片检查显示，标记水平显著降低。在这些样品中，在相同的区域只检测到少量分散的金颗粒。在干旱胁迫8 d后重新浇水3 d的植物叶片组织中，标记模式与定期浇水的植物相似。据我们所知，PTGRP是第一个精确定位于细胞壁的干旱调节蛋白。
A cDNA clone encoding a proline-, threonine-, and glycine-rich protein (PTGRP) was isolated from a wild tomato species (Lycopersicon chilense) (L.X. Yu, H. Chamberland, J.G. Lafontain, Z. Tabaeizadeh [1996] Genome 39: 1185-1193). Northern-blot analysis and in situ hybridization studies revealed that PTGRP is downregulated by drought stress. The level of the mRNA in leaves and stems of 8-d drought-stressed plants decreased 5- to 10-fold compared with that in regularly watered plants. The mRNA reaccumulated when drought-stressed plants were rewatered. Antibodies raised against a glutathione S-transferase/PTGRP fusion protein were used to elucidate the subcellular localization of the protein by immunogold labeling. In regularly watered L. chilense plants, PTGRP protein was found to be localized in xylem pit membranes and disintegrated primary walls. Examination of sections from drought-stressed plants revealed a significant decrease in the levels of labeling. In these samples, only a few scattered gold particles were detected in the same areas. In the leaf tissues of plants that had been rewatered for 3 d following an 8-d drought stress, the labeling pattern was similar to that of the regularly watered plants. To our knowledge, PTGRP is the first drought-regulated protein that has been precisely localized in the cell wall.