The negative regulator of plant cold responses, HOS1, is a RING E3 ligase that mediates the ubiquitination and degradation of ICE1
The negative regulator of plant cold responses, HOS1, is a RING E3 ligase that mediates the ubiquitination and degradation of ICE1
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植物冷反应的负调节因子 HOS1 是一种 RING E3 连接酶，介导 ICE1 的泛素化和降解
DOI：
10.1073/pnas.0602874103
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发表时间：
2006-05-23
影响因子：
11.1
通讯作者：
Zhu, Jian-Kang
中科院分区：
文献类型：
--
作者：
Dong, Chun-Hai;Agarwal, Manu;Zhu, Jian-Kang
植物对冷胁迫的响应是通过转录级联反应介导的，其中转录因子ICE1和可能相关的蛋白激活C-repeat (CRT)-binding factors （CBFs）的表达，导致下游效应基因的转录。高表达渗透反应基因（HOS）1的变异无名指蛋白被遗传学鉴定为冷反应的负调控因子。我们提供的证据表明，HOS1是ICE1泛素化所需的E3连接酶。在体内和体外，HOS1与ICE1相互作用并介导ICE1的泛素化。我们发现寒冷诱导植物中ICE1的降解，而这种降解需要ho1。与丧失功能的hos1突变植物中冷响应基因表达增强一致，hos1过表达会抑制cbf及其下游基因的表达，并增加对冷冻胁迫的敏感性。我们的研究结果表明，拟南芥的冷胁迫反应通过一个泛素化/蛋白酶体途径减弱，其中HOS1介导ICE1蛋白的降解。
Plant responses to cold stress are mediated by a transcriptional cascade, in which the transcription factor ICE1 and possibly related proteins activate the expression of C-repeat (CRT)-binding factors (CBFs), leading to the transcription of downstream effector genes. The variant RING finger protein high expression of osmotically responsive gene (HOS)1 was identified genetically as a negative regulator of cold responses. We present evidence here that HOS1 is an E3 ligase required for the ubiquitination of ICE1. HOS1 physically interacts with ICE1 and mediates the ubiquitination of ICE1 both in vitro and in vivo. We found that cold induces the degradation of ICE1 in plants, and this degradation requires HOS1. Consistent with enhanced cold-responsive gene expression in loss-of-function hos1 mutant plants, overexpression of HOS1 represses the expression of CBFs and their downstream genes and confers increased sensitivity to freezing stress. Our results indicate that cold stress responses in Arabidopsis are attenuated by a ubiquitination/proteasome pathway in which HOS1 mediates the degradation of the ICE1 protein.