Two Putative RNA-Binding Proteins Function with Unequal Genetic Redundancy in the MOS4-Associated Complex
Two Putative RNA-Binding Proteins Function with Unequal Genetic Redundancy in the MOS4-Associated Complex
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DOI：
10.1104/pp.110.158931
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发表时间：
2010-12-01
期刊：
影响因子：
7.4
通讯作者：
Li, Xin
中科院分区：
文献类型：
--
作者：
Monaghan, Jacqueline;Xu, Fang;Li, Xin
MOS 4相关复合物（MAC）是一种高度保守的与剪接体相关的核蛋白复合物。我们最近从拟南芥（Arabidopsis thaliana）细胞核中纯化了MAC，通过质谱鉴定了其潜在的组分，并表明MAC中至少有五个核心蛋白是植物防御反应所必需的。在这里，我们报告的MAC命名为MAC 5A和它的密切同系物MAC 5 B中确定的一个假定的RNA结合蛋白的表征。我们证实，MAC 5A是MAC的一个组成部分，通过与先前描述的MAC蛋白细胞分裂周期5拟南芥。此外，与所有其它特征性MAC蛋白一样，与绿色荧光蛋白融合的MAC 5A定位于细胞核。双突变体分析表明，MAC 5A和MAC 5 B是不相等的冗余，双mac 5a mac 5 b突变体导致致死性。可能是由于这种部分冗余，mac 5a和mac 5 b单突变体不表现出增强的易感性，有毒或无毒的病原体感染。然而，与其他MAC突变一样，mac 5a-1部分抑制npr 1 -1组成型1（snc 1）抑制因子的自身免疫表型，snc 1是一种表达失调的抗性蛋白的功能获得性突变体。我们的研究结果表明，MAC 5A是MAC的一个组成部分，有助于snc 1介导的自身免疫。
The MOS4-associated complex (MAC) is a highly conserved nuclear protein complex associated with the spliceosome. We recently purified the MAC from Arabidopsis (Arabidopsis thaliana) nuclei, identified its potential components by mass spectrometry, and showed that at least five core proteins in the MAC are required for defense responses in plants. Here, we report the characterization of a putative RNA-binding protein identified in the MAC named MAC5A and its close homolog MAC5B. We confirmed that MAC5A is a component of the MAC through coimmunoprecipitation with the previously described MAC protein CELL DIVISION CYCLE5 from Arabidopsis. In addition, like all other characterized MAC proteins, MAC5A fused to the Green Fluorescent Protein localizes to the nucleus. Double mutant analysis revealed that MAC5A and MAC5B are unequally redundant and that a double mac5a mac5b mutant results in lethality. Probably due to this partial redundancy, mac5a and mac5b single mutants do not exhibit enhanced susceptibility to virulent or avirulent pathogen infection. However, like other MAC mutations, mac5a-1 partially suppresses the autoimmune phenotypes of suppressor of npr1-1, constitutive1 (snc1), a gain-of-function mutant that expresses a deregulated Resistance protein. Our results suggest that MAC5A is a component of the MAC that contributes to snc1-mediated autoimmunity.