Expression of ER quality control-related genes in response to changes in BiP1 levels in developing rice endosperm
Expression of ER quality control-related genes in response to changes in BiP1 levels in developing rice endosperm
复制标题
DOI：
10.1111/j.1365-313x.2010.04453.x
复制
发表时间：
2011-03-01
期刊：
影响因子：
7.2
通讯作者：
Takaiwa, Fumio
中科院分区：
文献类型：
--
作者：
Wakasa, Yuhya;Yasuda, Hiroshi;Takaiwa, Fumio
P>结合蛋白 (BiP) 是参与内质网腔内种子储存蛋白等分泌蛋白折叠的关键伴侣。为了获得 BiP1（一种在水稻种子成熟过程中主要表达的基因）的功能信息，我们培育了几种转基因水稻植物，其中不同水平的 BiP1 蛋白以胚乳特异性方式积累。 BiP1的严重抑制（BiP1 KD）或显着过表达（BiP1 OEmax）不仅改变了种子表型和胚乳细胞的细胞内结构，而且降低了种子贮藏蛋白含量、淀粉积累和粒重。微阵列和RT-PCR分析表明，许多伴侣和辅助伴侣基因在转基因植物中被诱导表达，其中BiP1 KD系中的表达比BiP1 OEmax系中的表达更为显着。在用二硫苏糖醇或衣霉素处理的愈伤组织中观察到大多数伴侣蛋白的转录诱导，这些处理触发内质网应激，表明转基因水稻中伴侣基因的诱导是由内质网应激反应引起的。在使用水稻原生质体的瞬时测定中，AtbZIP60 转录因子的直系同源物 (Os06g0622700) 被证明参与了一些伴侣基因的激活。与野生型相比，BiP1水平略有增加，伴随着钙连接蛋白和蛋白质二硫键异构酶样蛋白水平的增加，导致种子贮藏蛋白含量显着增加，而细胞内结构或种子表型没有任何变化。明智地修改转基因水稻中的 BiP1 水平可以通过减轻 ER 应激来为分泌蛋白的产生提供合适的条件。
P>Binding protein (BiP) is the key chaperone involved in folding of secretory proteins such as seed storage proteins in the ER lumen. To obtain functional information about BiP1, a gene that is predominantly expressed during rice seed maturation, we generated several transgenic rice plants in which various levels of BiP1 protein accumulated in an endosperm-specific manner. Severe suppression (BiP1 KD) or significant over-expression (BiP1 OEmax) of BiP1 not only altered seed phenotype and the intracellular structure of endosperm cells, but also reduced seed storage protein content, starch accumulation and grain weight. Microarray and RT-PCR analyses indicated that expression of many chaperone and co-chaperone genes was induced in transgenic plants, with more prominent expression in the BiP1 KD line than in the BiP1 OEmax line. Transcriptional induction of most chaperones was observed in calli treated with dithiothreitol or tunicamycin, treatments that trigger ER stress, indicating that induction of the chaperone genes in transgenic rice was caused by an ER stress response. In transient assays using rice protoplasts, the ortholog (Os06g0622700) of the AtbZIP60 transcription factor was shown to be involved in activation of some chaperone genes. Slight increases in the BiP1 level compared with wild-type, accompanied by increased levels of calnexin and protein disulfide isomerase-like proteins, resulted in significant enhancement of seed storage protein content, without any change in intracellular structure or seed phenotype. Judicious modification of BiP1 levels in transgenic rice can provide suitable conditions for the production of secretory proteins by alleviating ER stress.