Lee Y, Choi D, Kende H
MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
Curr Opin Plant Biol. 2001 Dec;4(6):527-32. doi: 10.1016/s1369-5266(00)00211-9.
Expansins were first identified as cell-wall-loosening proteins that, at least in part, mediate pH-dependent extension of the plant cell wall and growth of the cell. More recently, it has been realized that expansins belong to two protein families, the alpha-and beta-expansins, and that they appear to be involved in regulating, besides cell expansion, a variety of plant processes, including morphogenesis, softening of fruits, and growth of the pollen tube of grasses through the stigma and the style. The Arabidopsis genome contains 26 alpha-expansin genes and the rice genome at least 26. There are more beta-expansin genes in monocots than in dicots, at least 14 in rice and five in Arabidopsis. Expansin genes are differentially regulated by environmental and hormonal signals, and hormonal regulatory elements have been found in their promoter regions. An analysis of exon/intron structure led to the hypothesis that alpha-and beta-expansins evolved from a common ancestral gene.
扩张蛋白最初被鉴定为细胞壁松弛蛋白，至少部分介导植物细胞壁的pH依赖性伸展和细胞生长。最近，人们认识到扩张蛋白属于两个蛋白家族，即α-扩张蛋白和β-扩张蛋白，并且它们似乎除了参与细胞扩张外，还参与调节多种植物过程，包括形态发生、果实软化以及禾本科植物花粉管通过柱头和花柱的生长。拟南芥基因组包含26个α-扩张蛋白基因，水稻基因组至少有26个。单子叶植物中的β-扩张蛋白基因比双子叶植物中的多，水稻中至少有14个，拟南芥中有5个。扩张蛋白基因受环境和激素信号的差异调节，并且在其启动子区域发现了激素调节元件。外显子/内含子结构分析得出一个假说，即α-扩张蛋白和β-扩张蛋白是由一个共同的祖先基因进化而来的。
