玉米泛素延伸蛋白基因ZmERD16的克隆、序列特征和表达分析

在前期研究中发现一个玉米苗期早期应答干旱的EST序列与拟南芥泛素延伸蛋白ERD16序列同源性很高。本研究根据拟南芥AtERD16序列，应用同源克隆技术分离出玉米泛素延伸蛋白基因，命名为ZmERD16。ZmERD16的开放阅读框为390 bp，编码129个氨基酸，等电点pI为 9.94，分子量为14.7582 kD。ZmERD16蛋白包含1个泛素单体蛋白，其后融合了53个氨基酸的核糖体多肽，属于泛素延伸蛋白亚族。ZmERD16具有4个外显子3个内含子的基因组结构，其启动子区域具有多个干旱、病害、水杨酸、乙烯、真菌等胁迫响应应答元件。蛋白结构预测显示ZmERD16无跨膜结构，定位于细胞质和细胞核中。利用实时荧光定量PCR对ZmERD16的组织表达特异性和在不同胁迫条件下的表达谱分析表明，ZmERD16在各组织中均表达，其表达量受盐、脱水、PEG、低温、高温、茉莉酸甲酯和水杨酸等多种胁迫信号诱导。推测ZmERD16可能参与玉米的多种胁迫信号传导和逆境应答进程。

Identification and Expression Analysis of ZmERD16: a Ubiquitin Extension Protein Gene in Maize (Zea mays L.)

Ubiquitin extension protein is a fusion prot0ein of an ubiquitin monomer followed by a ribosomal protein with 52–53 animo acids or 76–78 amino acids. Ubiquitin extension proteins have been paid attention that they play important roles in responding to stresses and regulating certain developmental processes in plants. We describe here the isolation, sequence characteristics and expression analysis of ZmERD16 gene encoding a homologue of ubiquitin extension protein. ZmERD16 includes a 390 bp open reading frame (ORF) encoding an ubiquitin monomer followed by 53 animo acids, with a predicted molecular mass of 14.7582 kD and pI of 9.94. The genomic DNA and the promoter region of ZmERD16 were obtained by PCR method. The genomic DNA was composed of four exons and three introns. Promoter had some motifs that were related to light, stress, defense, development, auxin and other stresses. The tissue-specific expression analysis suggested that ZmERD16 was constitutively expressed in maize different tissues. Quantitative real-time RT-PCR results showed ZmERD16 was a multiple stresses inducible gene, induced by various stresses, such as salt, dehydration, cold, heat, PEG, methy jasmonat (MJ) and salicylic acid (SA), but not by ABA and 2,4-D. These results suggested that ZmERD16 might play an important role in various signal transduction pathways of stresses in plant.