Genetic Interactions Between BOB1 and Multiple 26S Proteasome Subunits Suggest a Role for Proteostasis in Regulating Arabidopsis Development.
Genetic Interactions Between BOB1 and Multiple 26S Proteasome Subunits Suggest a Role for Proteostasis in Regulating Arabidopsis Development.
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DOI：
10.1534/g3.118.300496
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发表时间：
2018-03-28
期刊：
影响因子：
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通讯作者：
Kaplinsky NJ
中科院分区：
文献类型：
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作者：
Silverblatt-Buser EW;Frick MA;Rabeler C;Kaplinsky NJ
蛋白质折叠和降解都是蛋白质质量控制所必需的，蛋白质质量控制是支撑正常生长和发育的基本细胞活动。我们研究了Bob1，一种拟南芥的小分子热休克蛋白，如何维持植物的正常发育。Bob1突变体表现出器官极性缺陷，并扩大了Knox基因的表达区域。这些表型中的一些是生态型特有的，这表明其他基因可以改变它们。使用遗传方法，我们确定了Bob1和FIL之间的相互作用，FIL是远轴器官识别所必需的基因。我们还使用Bob1-3等位基因进行了EMS增强子筛查，以确定因Bob1功能丧失而致敏的途径。这一筛选确定了Bob1和蛋白酶体亚单位RPT2a之间的遗传相互作用，但不是物理相互作用。另外两个蛋白酶体亚基RPN1a和RPN8a也与Bob1基因相互作用。Bob1和与Bob1相互作用的蛋白酶体亚基都已被证明与转录增强子AS1和AS2在遗传上相互作用，这两个基因已知调节器官极性和KNOX基因的表达。我们的结果提出了一种模型，在该模型中，Bob1介导的蛋白质折叠和蛋白酶体介导的蛋白质降解形成了确保植物正常发育所需的蛋白平衡功能模块。
Protein folding and degradation are both required for protein quality control, an essential cellular activity that underlies normal growth and development. We investigated how BOB1, an Arabidopsis thaliana small heat shock protein, maintains normal plant development. bob1 mutants exhibit organ polarity defects and have expanded domains of KNOX gene expression. Some of these phenotypes are ecotype specific suggesting that other genes function to modify them. Using a genetic approach we identified an interaction between BOB1 and FIL, a gene required for abaxial organ identity. We also performed an EMS enhancer screen using the bob1-3 allele to identify pathways that are sensitized by a loss of BOB1 function. This screen identified genetic, but not physical, interactions between BOB1 and the proteasome subunit RPT2a. Two other proteasome subunits, RPN1a and RPN8a, also interact genetically with BOB1. Both BOB1 and the BOB1-interacting proteasome subunits had previously been shown to interact genetically with the transcriptional enhancers AS1 and AS2, genes known to regulate both organ polarity and KNOX gene expression. Our results suggest a model in which BOB1 mediated protein folding and proteasome mediated protein degradation form a functional proteostasis module required for ensuring normal plant development.