The Arabidopsis CONSTITUTIVE EXPRESSER of PATHOGENESIS-RELATED GENES 5 (CPR5) has recently been shown to play a role in gating as part of the nuclear pore complex (NPC). Mutations in CPR5 cause multiple defects, including aberrant trichomes, reduced ploidy levels, reduced growth and enhanced resistance to bacterial and fungal pathogens. The pleiotropic nature of cpr5 mutations implicates that the CPR5 protein affects multiple pathways. However, little is known about the structural features that allow CPR5 to affect the different pathways. Our in silico studies suggest that in addition to three clusters of putative nuclear localization signals and four or five transmembrane domains, CPR5 contains two putative alternative translation start sites. To test the role of the methionine-encoding nucleotides implicated in those sites, metCPR5 cDNAs, in which the relevant nucleotides were changed to encode glutamine, were fused to the CPR5 native promoter and the constructs transformed to cpr5–2 plants to complement cpr5-compromised phenotypes. The control and metCPR5 constructs were able to complement all cpr5 phenotypes, although the extent of complementation depended on the specific complementing plant lines. Remarkably, plants transformed with metCPR5 constructs showed larger leaves and displayed reduced resistance when challenged to Pseudomonas syringae pv Pst DC3000, as compared to control plants. Thus, the methionine-encoding nucleotides regulate growth and resistance. We propose that structural features of the CPR5 N-terminus are implicated in selective gating of proteins involved in regulating the balance between growth and resistance. Plants need to carefully balance the amount of resources used for growth and resistance. The Arabidopsis CPR5 protein regulates plant growth and immunity. Here we show that N-terminal features of CPR5 are involved in the regulation of the balance between growth and resistance. These findings may benefit efforts to improve plant yield, while maintaining optimal levels of disease resistance.

中文翻译：

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假定的替代翻译起始位点编码的CPR5核苷酸调节生长和抗性。

病原性相关基因5（CPR5）的拟南芥组成型表达物最近被证明在门控中起着核孔复合体（NPC）的作用。CPR5的突变会引起多种缺陷，包括毛状体异常，倍数水平降低，生长降低以及对细菌和真菌病原体的抗性增强。cpr5突变的多效性暗示CPR5蛋白影响多种途径。但是，对于允许CPR5影响不同途径的结构特征知之甚少。我们的计算机研究表明，除了三个簇的假定核定位信号和四个或五个跨膜结构域之外，CPR5还包含两个假定的替代翻译起始位点。为了测试与这些位点有关的蛋氨酸编码核苷酸（metCPR5 cDNA）的作用，其中相关的核苷酸被改变以编码谷氨酰胺，被融合到CPR5天然启动子上，构建体被转化为cpr5–2植物以补充cpr5受损的表型。对照和metCPR5构建体能够互补所有cpr5表型，尽管互补的程度取决于特定的互补植物株系。值得注意的是，与对照植物相比，当用丁香假单胞菌pv Pst DC3000攻击时，用metCPR5构建体转化的植物显示出较大的叶片并显示出降低的抗性。因此，蛋氨酸编码核苷酸调节生长和抗性。我们提出，CPR5 N末端的结构特征与参与调节生长与抗性平衡的蛋白质的选择性门控有关。植物需要谨慎地平衡用于增长和抵抗的资源量。拟南芥CPR5蛋白调节植物的生长和免疫。在这里，我们显示CPR5的N末端特征参与了生长与抗性之间平衡的调节。这些发现可能有益于提高植物产量同时保持最佳抗病性水平的努力。