Arabidopsis SAP5 functions as a positive regulator of stress responses and exhibits E3 ubiquitin ligase activity
Arabidopsis SAP5 functions as a positive regulator of stress responses and exhibits E3 ubiquitin ligase activity
复制标题
DOI：
10.1007/s11103-011-9748-2
复制
发表时间：
2011-03-01
影响因子：
5.1
通讯作者：
Allen, Randy D.
中科院分区：
文献类型：
--
作者：
Kang, Miyoung;Fokar, Mohamed;Allen, Randy D.
AtSAP 5是拟南芥中胁迫相关蛋白基因家族的14个成员之一，通过其在盐、渗透、干旱和冷胁迫下的表达来鉴定。AtSAP 5与水稻中与胁迫耐受性有关的A20/AN 1型锌指蛋白OSISAP 1具有很强的同源性。为了评估AtSAP 5在非生物胁迫应答调节中的功能，表征了过表达AtSAP 5（35 S：：AtSAP 5）的转基因拟南芥植物，沿着野生型和T-DNA敲低植物。过表达AtSAP 5的植物表现出对包括盐胁迫、渗透胁迫和水分亏缺在内的环境挑战的耐受性增加。在正常条件下和水分胁迫下，35 S：：AtSAP 5转基因植株和野生型植株之间的基因表达模式的比较表明，AtSAP 5的过度表达与干旱胁迫响应基因表达的上调相关。对表达GFP-AtSAP 5的转基因植物的分析表明，它主要定位于根细胞的细胞核中，并且重组AtSAP 5在体外具有E3泛素连接酶活性。这些结果表明AtSAP 5具有E3连接酶活性，并在拟南芥中作为胁迫反应的正调节因子。
AtSAP5, one of approximately 14 members of the Stress Associated Protein gene family in Arabidopsis, was identified by its expression in response to salinity, osmotic, drought and cold stress. AtSAP5 shows strong homology to OSISAP1, an A20/AN1-type zinc finger protein implicated in stress tolerance in rice. To evaluate the function of AtSAP5 in the regulation of abiotic stress responses, transgenic Arabidopsis plants that over-express AtSAP5 (35S::AtSAP5) were characterized, along with wild-type and T-DNA knock-down plants. Plants that over-express AtSAP5 showed increased tolerance to environmental challenges including salt stress, osmotic stress and water deficit. Comparison of gene expression patterns between 35S:: AtSAP5 transgenic plants and wild-type plants under normal conditions and water deficit stress indicated that over-expression of AtSAP5 correlates with up-regulation of drought stress responsive gene expression. Analysis of transgenic plants that express GFP-AtSAP5 showed that it is localized primarily in nuclei of root cells and recombinant AtSAP5 has E3 ubiquitin ligase activity in vitro. These results indicate that AtSAP5 has E3 ligase activity and acts as a positive regulator of stress responses in Arabidopsis.