Molecular and functional characterization of Arabidopsis Cullin 3A
Molecular and functional characterization of Arabidopsis Cullin 3A
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DOI：
10.1111/j.1365-313x.2004.02302.x
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发表时间：
2005-02-01
期刊：
影响因子：
7.2
通讯作者：
Genschik, P
中科院分区：
文献类型：
--
作者：
Dieterle, M;Thomann, A;Genschik, P
库林蛋白在真核生物中属于多基因家族，与其他蛋白结合形成泛素蛋白连接酶(Ubiquitin Protein Ligase，E3S)，作为26S蛋白酶体降解底物的靶标。在这里，我们介绍了一种植物cullin3的分子和遗传特征。与真菌和动物不同，模式植物拟南芥的基因组中包含两个相关的CUL3基因，分别称为CUL3A和CUL3B。我们发现CUL3A在植物中广泛表达，并且能够与环指蛋白RBX1相互作用。基因组搜索显示，拟南芥中至少存在76个BTB结构域蛋白，分别属于11个主要家族。酵母双杂交实验表明，某些家族的代表性成员能够与CUL3A和CUL3B发生物理相互作用，这表明拟南芥CUL3与某些BTB结构域蛋白形成E3蛋白复合体。为了确定CUL3A的功能，我们使用了反向遗传学方法。Cul3a缺失突变体的开花略晚于对照植株。此外，该突变体在远红光下表现出对抑制下胚轴生长的敏感性降低，并缺失表达COP1。突变植株的生存能力表明，拟南芥中的两个CUL3基因之间存在功能冗余。
Cullin proteins, which belong to multigenic families in all eukaryotes, associate with other proteins to form ubiquitin protein ligases (E3s) that target substrates for proteolysis by the 26S proteasome. Here, we present the molecular and genetic characterization of a plant Cullin3. In contrast to fungi and animals, the genome of the model plant Arabidopsis thaliana contains two related CUL3 genes, called CUL3A and CUL3B. We found that CUL3A is ubiquitously expressed in plants and is able to interact with the ring-finger protein RBX1. A genomic search revealed the existence of at least 76 BTB-domain proteins in Arabidopsis belonging to 11 major families. Yeast two-hybrid experiments indicate that representative members of certain families are able to physically interact with both CUL3A and CUL3B, suggesting that Arabidopsis CUL3 forms E3 protein complexes with certain BTB domain proteins. In order to determine the function of CUL3A, we used a reverse genetic approach. The cul3a null mutant flowers slightly later than the control plants. Furthermore, this mutant exhibits a reduced sensitivity of the inhibition of hypocotyl growth in far-red light and miss-expresses COP1. The viability of the mutant plants suggests functional redundancy between the two CUL3 genes in Arabidopsis.