Eliasson A, Gass N, Mundel C, Baltz R, Kräuter R, Evrard J L, Steinmetz A
Institut de Biologie Moléculaire des Plantes du CNRS, Strasbourg, France.
Mol Gen Genet. 2000 Oct;264(3):257-67. doi: 10.1007/s004380000312.
LIM-domain proteins participate in important cellular processes in eukaryotes, including gene transcription and actin cytoskeleton organization. They are predominantly found in animals, but have also been identified in yeast and plants. Following the characterization ofa LIM-domain protein in sunflower pollen, we carried out an extensive search for these proteins in flowering plants. We have isolated and studied cDNAs and/or genomic sequences for two novel LIM-domain proteins from sunflower, three from tobacco, and one from Arabidopsis. The plant proteins are structurally related to the cytoskeleton-associated CRP class of LIM proteins in animals, but show several distinctive features, including a second, atypical, LIM domain. We have performed comparative expression studies of these genes, as well as of one other gene from tobacco and two additional Arabidopsis genes whose sequences are available from databases. These studies, carried out by RT-PCR in the presence of gene-specific primers, showed that, in sunflower and tobacco, pollen grains and sporophytic tissues express different sets of LIM proteins. With the exception of one Arabidopsis gene--which has two introns--all the genes analyzed contain four introns at conserved positions, indicating that the ancestral gene from which the various copies evolved in higher plants allready had this split structure.
LIM结构域蛋白参与真核生物重要的细胞过程，包括基因转录和肌动蛋白细胞骨架组织。它们主要存在于动物中，但在酵母和植物中也已被鉴定出来。在对向日葵花粉中的一种LIM结构域蛋白进行表征之后，我们在开花植物中对这些蛋白进行了广泛搜索。我们已经分离并研究了来自向日葵的两种新型LIM结构域蛋白、来自烟草的三种以及来自拟南芥的一种的cDNA和/或基因组序列。这些植物蛋白在结构上与动物中与细胞骨架相关的CRP类LIM蛋白相关，但具有几个独特的特征，包括第二个非典型的LIM结构域。我们对这些基因以及来自烟草的另一个基因和另外两个可从数据库获得序列的拟南芥基因进行了比较表达研究。这些通过在基因特异性引物存在下进行RT-PCR的研究表明，在向日葵和烟草中，花粉粒和孢子体组织表达不同的LIM蛋白组。除了一个拟南芥基因（有两个内含子）之外，所有分析的基因在保守位置都含有四个内含子，这表明高等植物中各个拷贝所演化而来的祖先基因已经具有这种分裂结构。
