Plant Sciences Institute, Iowa State University, Ames, IA 50011, USA.
Proc Natl Acad Sci U S A. 2011 Apr 26;108(17):7247-52. doi: 10.1073/pnas.1102117108. Epub 2011 Apr 11.
Adverse environmental conditions produce endoplasmic reticulum (ER) stress in plants. In response to heat or ER stress agents, Arabidopsis seedlings mitigate stress damage by activating ER-associated transcription factors and a RNA splicing factor, IRE1b. IRE1b splices the mRNA-encoding bZIP60, a basic leucine-zipper domain containing transcription factor associated with the unfolded protein response in plants. bZIP60 is required for the up-regulation of BINDING PROTEIN3 (BIP3) in response to ER stress, and loss-of-function mutations in IRE1b or point mutations in the splicing site of bZIP60 mRNA are defective in BIP3 induction. These findings demonstrate that bZIP60 in plants is activated by RNA splicing and afford opportunities for monitoring and modulating stress responses in plants.
逆境条件会给植物的内质网（ER）带来压力。为了应对热或 ER 应激因子，拟南芥幼苗通过激活 ER 相关转录因子和 RNA 剪接因子 IRE1b 来减轻应激损伤。IRE1b 剪接编码 bZIP60 的 mRNA，bZIP60 是一种碱性亮氨酸拉链结构域转录因子，与植物中未折叠蛋白反应有关。bZIP60 是响应 ER 应激时上调 BINDING PROTEIN3（BIP3）所必需的，并且 IRE1b 的功能丧失突变或 bZIP60 mRNA 剪接位点的点突变在 BIP3 诱导中是有缺陷的。这些发现表明，植物中的 bZIP60 是通过 RNA 剪接激活的，为监测和调节植物的应激反应提供了机会。
