Cold Shock Domain Protein 3 Regulates Freezing Tolerance in Arabidopsis thaliana
Cold Shock Domain Protein 3 Regulates Freezing Tolerance in Arabidopsis thaliana
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DOI：
10.1074/jbc.m109.025791
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发表时间：
2009-08-28
影响因子：
4.8
通讯作者：
Imai, Ryozo
中科院分区：
文献类型：
--
作者：
Kim, Myung-Hee;Sasaki, Kentaro;Imai, Ryozo
大肠杆菌对冷的反应是产生冷休克蛋白（CSPs），作为RNA分子伴侣在冷适应中起重要作用。在这里，我们表明，拟南芥冷休克结构域蛋白3（AtCSP 3），其中共享一个冷休克结构域与细菌CSP，参与收购植物的抗冻性。AtCSP 3补充了E. coli CSP四倍体突变体，并显示核酸双链体解链活性，表明AtCSP 3也具有RNA伴侣的功能。启动子-GUS转基因植株显示AtCSP 3在地上部和根尖区域的组织特异性表达。当暴露于低温时，GUS活性被广泛诱导在更广泛的区域的根。在表达AtCSP 3-GFP融合体的转基因植物中，在细胞核和细胞质中都检测到GFP信号。AtCSP 3基因敲除突变体（atcsp 3 -2）在非驯化和冷驯化条件下与野生型植物相比对冷冻敏感，而在atcsp 3 -2突变体中，在冷驯化过程中C-重复序列结合因子及其下游基因的表达没有改变。AtCSP 3在转基因植物中的过表达赋予了比野生型植物增强的抗冻性。总之，这些数据证明了RNA伴侣在高等植物冷适应中的重要作用。
In response to cold, Escherichia coli produces cold shock proteins (CSPs) that have essential roles in cold adaptation as RNA chaperones. Here, we demonstrate that Arabidopsis cold shock domain protein 3 (AtCSP3), which shares a cold shock domain with bacterial CSPs, is involved in the acquisition of freezing tolerance in plants. AtCSP3 complemented a cold-sensitive phenotype of the E. coli CSP quadruple mutant and displayed nucleic acid duplex melting activity, suggesting that AtCSP3 also functions as an RNA chaperone. Promoter-GUS transgenic plants revealed tissue-specific expression of AtCSP3 in shoot and root apical regions. When exposed to low temperature, GUS activity was extensively induced in a broader region of the roots. In transgenic plants expressing an AtCSP3-GFP fusion, GFP signals were detected in both the nucleus and cytoplasm. An AtCSP3 knock-out mutant (atcsp3-2) was sensitive to freezing compared with wild-type plants under non-acclimated and cold-acclimated conditions, whereas expression of C-repeat-binding factors and their downstream genes during cold acclimation was not altered in the atcsp3-2 mutant. Overexpression of AtCSP3 in transgenic plants conferred enhanced freezing tolerance over wild-type plants. Together, the data demonstrated an essential role of RNA chaperones for cold adaptation in higher plants.