Proteomic and transcriptomic analysis of Arabidopsis seeds: molecular evidence for successive processing of seed proteins and its implication in the stress response to sulfur nutrition
Proteomic and transcriptomic analysis of Arabidopsis seeds: molecular evidence for successive processing of seed proteins and its implication in the stress response to sulfur nutrition
复制标题
DOI：
10.1111/j.1365-313x.2006.02900.x
复制
发表时间：
2006-11-01
期刊：
影响因子：
7.2
通讯作者：
Saito, Kazuki
中科院分区：
文献类型：
--
作者：
Higashi, Yasuhiro;Hirai, Masami Yokota;Saito, Kazuki
种子贮藏蛋白是作为下一代植物的碳、氮和硫的来源而合成的。它们的组成根据营养条件而变化。在这里，我们报告了通过对野生型拟南芥和甲硫氨酸过度积累突变体mto 1 -1植物进行蛋白质组学分析来精确分子鉴定种子蛋白的结果。通过双向凝胶电泳和质谱分析确定了成熟拟南芥种子蛋白提取物中50个蛋白质点的身份。在这些蛋白质点中，42个被鉴定为来自12 S球蛋白或2S白蛋白。这些结果表明，拟南芥种子中约84%的蛋白质种类来自于编码12 S球蛋白和2S白蛋白的少数基因。对42个点进行广泛的质谱分析表明，12 S球蛋白上发生了连续的C-末端降解。通过对12 S球蛋白的三维结构进行分子建模，使这种C-末端加工的可行性合理化。在缺硫条件下，12 S球蛋白亚基的谷氨酸残基的C-末端降解被抑制。转录组分析与蛋白质组学分析相结合，以阐明种子蛋白质组成的变化响应缺硫的机制。结果表明，拟南芥种子贮藏蛋白经历多层调节，重点是使植物能够对硫缺乏做出反应的翻译后修饰。
Seed storage proteins are synthesized as sources of carbon, nitrogen and sulfur for the next generation of plants. Their composition changes according to nutritional conditions. Here, we report the precise molecular identification of seed proteins by proteomic analysis of wild-type Arabidopsis thaliana and methionine-over-accumulating mutant mto1-1 plants. The identities of 50 protein spots were determined in the protein extract of mature Arabidopsis seeds by two-dimensional (2D) gel electrophoresis and subsequent mass spectrometric analysis. Of these protein spots, 42 were identified as derived from 12S globulins or 2S albumins. These results indicate that approximately 84% of protein species in Arabidopsis seeds are derived from a few genes coding for 12S globulins and 2S albumins. Extensive mass spectrometric analysis of the 42 spots revealed that successive C-terminal degradation occurred on the 12S globulins. The feasibility of this C-terminal processing was rationalized by molecular modeling of the three-dimensional structure of 12S globulins. The C-terminal degradation at glutamic acid residues of the 12S globulin subunits was repressed under sulfur-deficient conditions. Transcriptome analysis was combined with proteomic analysis to elucidate the mechanism of changes in seed protein composition in response to sulfur deficiency. The results suggest that seed storage proteins in Arabidopsis undergo multi-layer regulation, with emphasis on post-translational modifications that enable the plant to respond to sulfur deficiency.