Characterization of a novel class of plant homeodomain proteins that bind to the C4 phosphoenolpyruvate carboxylase gene of Flaveria trinervia
Characterization of a novel class of plant homeodomain proteins that bind to the C4 phosphoenolpyruvate carboxylase gene of Flaveria trinervia
复制标题
DOI：
10.1023/a:1006450005648
复制
发表时间：
2001-01-01
影响因子：
5.1
通讯作者：
Stockhaus, J
中科院分区：
文献类型：
--
作者：
Windhövel, A;Hein, I;Stockhaus, J
我们对C-4磷酸烯醇丙酮酸羧化酶（PEPCase）的叶肉特异性表达的调控机制感兴趣。单杂交筛选结果克隆了一类新的植物同源结构域蛋白的4个不同成员，这些蛋白很可能参与了黄草属C-4种中C-4 PEPCase基因的叶肉特异性表达。对这四种蛋白的同位结构域的检查表明，它们与迄今为止描述的同位结构域具有许多共同特征，但也存在显着差异。有趣的是，这类同源结构域蛋白也存在于拟南芥和其他C-3植物中。单杂交实验和体外DNA结合研究证实，这些新的同源结构域蛋白特异性地与C-4 PEPCase基因的近端区域相互作用。同源结构域蛋白的n端结构域包含高度保守的序列基序。双杂交实验表明，这些基序足以在蛋白质之间形成同源或异源二聚体。在二聚化结构域中保守的半胱氨酸残基的突变表明这些残基对二聚体的形成是必不可少的。因此，我们将这类新的同源结构域蛋白命名为ZF-HD，即锌指同源结构域蛋白。我们的数据表明，ZF-HD类同源结构域蛋白可能参与了C-4 PEPCase基因特征表达模式的建立。
We are interested in the regulatory mechanisms responsible for the mesophyll-specific expression of C-4 phosphoenolpyruvate carboxylase (PEPCase). A one-hybrid screen resulted in the cloning of four different members of a novel class of plant homeodomain proteins, which are most likely involved in the mesophyll-specific expression of the C-4 PEPCase gene in C-4 species of the genus Flaveria. inspection of the homeodomains of the four proteins reveals that they share many common features with homeodomains described so far, but there are also significant differences. Interestingly, this class of homeodomain proteins occurs also in Arabidopsis thaliana and other C-3 plants. One-hybrid experiments as well as in vitro, DNA binding studies confirmed that these novel homeodomain proteins specifically interact with the proximal region of the C-4 PEPCase gene. The N-terminal domains of the homeodomain proteins contain highly conserved sequence motifs. Two-hybrid experiments show that these motifs are sufficient to confer homo- or heterodimer formation between the proteins. Mutagenesis of conserved cysteine residues within the dimerization domain indicates that these residues are essential for dimer formation. Therefore, we designate this novel class of homeobox proteins ZF-HD, for zinc finger homeodomain protein. Our data suggest that the ZF-HD class of homeodomain proteins may be involved in the establishment of the characteristic expression pattern of the C-4 PEPCase gene.