【摘要】 油菜素甾醇(Brassinosteroid,BR)是一类重要的调控植物生长发育的激素,BKI1在BR信号转导通路中具有正负调控的双重功能.为了深入研究BK11正/负调控BR信号通路的分子机制,本研究使用BKI1作为诱饵蛋白对拟南芥cDNA文库进行酵母双杂交筛选,获得了一段新的与BR信号通路组分BKI1相互作用的肽段,BLAST搜索显示该肽段与拟南芥ERD7的N端序列一致.生物信息学分析表明ERD7是一个植物特异表达基因,在单子叶、双子叶、以及低等植物中保持很高的一致性.酵母双杂交方法证实全长ERD7与BKI1能够相互作用,Pull-down分析证实这两个基因在植物体内直接相互作用,烟草细胞瞬时表达显示ERD7和BKI1能够共定位于细胞质和细胞膜.BKI1和ERD7相互作用的发现为进一步研究BKI1的调控机制奠定了基础.更多还原

【Abstract】 Brassinosteroids(BRs),the plant steroid hormones,play important roles in regulating a wide range of plant growth and developmental processes.In absence of BRs,BKI1 acts negatively to inhibit the activity of BR receptor BRI1 in the plasma membrane; in the presence of BRs,BKI1 dissociates from plasma membrane and positively regulate BR signaling in cytosol.To further understand the function of BKI1,we used BKI1 as bait to screen Arabidopsis thaliana cDNA library and identified a new interacting peptide by yeast two-hybrid approach.BLAST search showed that the sequence of peptide was similar with parts of the N-terminus of ERD7.Bioinformatics analysis revealed that ERD7 was specifically expressed in plants and conserved in monocotyledon,dicots and lower plants.The interaction between the full-length ERD7 and BKI1 was confirmed via yeast two-hybrid and semi-in-vivo pull-down assay.Additionally,the subcellular localization of transiently overexpressed ERD7 and BKI1 was tested in the pavement cells of Nicotiana benthamiana,demonstrating that they could be co-localized in the cell membrane and cytoplasm.The identification of BKI1-interacting protein ERD7 is essential for further study on the regulation of BKI1.更多还原