Interaction with a Host Ubiquitin-Conjugating Enzyme Is Required for the Pathogenicity of a Geminiviral DNA β Satellite
Interaction with a Host Ubiquitin-Conjugating Enzyme Is Required for the Pathogenicity of a Geminiviral DNA β Satellite
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DOI：
10.1094/mpmi-22-6-0737
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发表时间：
2009-06-01
影响因子：
3.5
通讯作者：
Rezaian, M. Ali
中科院分区：
文献类型：
--
作者：
Eini, Omid;Dogra, Satish;Rezaian, M. Ali
DNA β是一种单链卫星DNA，编码一个基因β C1。为了更好地了解β C1在DNA β致病性中的作用，以棉花曲叶病毒（CLCuMV）木尔坦DNA β的β C1为诱饵，对番茄cDNA文库进行酵母双杂交筛选。确定了一种泛素缀合酶，命名为SlUBC 3，其在功能上补充了泛素缀合酶缺陷的酵母突变体。β C1和SlUBC 3之间相互作用的真实性和特异性在体内（使用双分子荧光互补测定法）和体外（使用蛋白结合测定法）都得到了证实。β C1蛋白的缺失突变体的分析表明，肉豆蔻酰化样基序是必需的，其与SlUBC 3的相互作用和在宿主植物中的DNA-β特异性症状的诱导。与野生型植物相比，发现表达β C1的转基因烟草植物中的多泛素化蛋白的水平降低。这些结果与β C1与SlUBC 3的相互作用是DNA-β特异性症状诱导所需的假设一致，并且这可能是由于宿主泛素蛋白酶体途径的下调。
DNA beta is a single-stranded satellite DNA which encodes a single gene, beta C1. To better understand the role of beta C1 in the pathogenicity of DNA beta, a yeast two-hybrid screen of a tomato cDNA library was carried out using beta C1 from Cotton leaf curl Multan virus (CLCuMV) DNA beta as the bait. A ubiquitin-conjugating enzyme, designated SlUBC3, which functionally complemented a yeast mutant deficient in ubiquitin-conjugating enzymes was identified. The authenticity and specificity of the interaction between beta C1 and SlUBC3 was confirmed both in vivo, using a bimolecular fluorescence complementation assay, and in vitro, using a protein-binding assay. Analysis of deletion mutants of the beta C1 protein showed that a myristoylation-like motif is required both for its interaction with SlUBC3 and the induction of DNA-beta-specific symptoms in host plants. The level of polyubiquitinated proteins in transgenic tobacco plants expressing beta C1 was found to be reduced compared with wild-type plants. These results are consistent with the hypothesis that interaction of beta C1 with SlUBC3 is required for DNA-beta-specific symptom induction, and that this is possibly due to downregulation of the host ubiquitin proteasome pathway.