Author: SHEN Yi-Guo,YAN Dong-Qing,ZHANG Wan-Ke,DU Bao-Xin,ZHANG Jin-Song,LIU Qiang,CHEN Shou-Yi
EREBP/AP2_type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respectively. To characterize transcription factors involved in plant responses to salt stress, we constructed cDNA library from salt_treated halophyte (Atriplex hortensis) and isolated a novel gene encoding EREBP/AP2_type protein from this library. This cDNA contained an ORF of 723 bp and a long 3′_Untranslated_Region (UTR) of 655 bp. The deduced amino acid sequence showed one conserved DNA binding domain of EREBP/AP2, thus the corresponding gene was named AhDREB1 with a calculated molecular mass of 26.1 kD. AhDREB1 under the control of CaMV 35S promoter was then transformed into tobacco and nine independent transgenic lines were obtained and subjected to long term salt stress. The results suggested that overexpression of AhDREB1 improved the salt tolerance in transgenic tobacco through functioning as a regulatory molecule in response to salt stress. Analysis of Arabidopsis genome in database resulted in dozens of EREBP/AP2_type homologous proteins, of which seven members showed high similarity to AhDREB1. Secondary structure analysis predicted similar arrangement of α_helix in their DNA binding domains.
山菠菜EREBP/AP2类DNA结合蛋白基因的克隆及其耐逆性研究
沈义国,闫冬青,张万科,杜保兴,张劲松,刘强,陈受宜
(1. 中国科学院遗传和发育生物学研究所,北京 100101;2. 西北农林科技大学生命科学学院,陕西杨凌 712100;3. 清华大学生物科学和生物技术系,北京 100084)
摘要: EREBP/AP2类蛋白是一个仅存在于植物中的DNA结合蛋白(DBP)大家族.其中一些成员如APETALA2和tDREB/CBF分别调控花的发育和植物对环境胁迫的反应.为了阐明在植物响应盐胁迫过程中所涉及的转录因子的特点,用高盐浓度处理盐生植物山菠菜,构建了cDNA文库,并从此文库中分离得到了一个编码EREBP/AP2类蛋白的基因.此cDNA包含一个723bp的开放读码框和一个长达655bp的3'端非编码区,推导的氨基酸序列显示其有一个保守的EREBP/AP2的DNA结合域,此基因被命名为AhDREB1.将AhDREB1置于CaMV 35S启动子下转入烟草,获得9个独立的转基因株系,对其进行了长期的盐胁迫实验.结果显示,AhDREB1的组成性表达显著提高了转基因烟草的耐盐能力,这可能是由于其激活了一些具有抗盐效应的下游基因.通过与拟南芥的全基因组进行同源性比较得到了具有较高相似性的7个EREBP/AP2家族成员,二级结构预测显示了它们在DNA结合区段的α螺旋结构上具有相似性.
关键词: 山菠菜; EREBP/AP2类DNA结合蛋白; 转基因烟草
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** 通讯作者。E-mail: sychen@genetics.ac.cn; qliu@mail.tsinghua.edu.cn。