商陆扩展蛋白基因PaEXP1在逆境胁迫下的表达

Expression of PaEXP1 from Phytolacca acinosa seedling in response to adversity

利用同源克隆的方法,从商陆中克隆得到扩展蛋白基因的全长cDNA序列,命名为PaEXP1(Gen Bank登录号为GQ851947).PaEXP1长1128bp,含有759bp的完整开放阅读框,编码252个氨基酸,分子量27.1kD,等电点8.55.PaEXP1氨基酸序列N端含有8个半胱氨酸残基,1个组氨酸(His-Phe-Asp,HFD)域,C末端存在4个保守的色氨酸残基,具有扩展蛋白的典型结构.系统进化树分析表明,PaEXP1属于扩展蛋白的α-扩展蛋白家族.Realtime-PCR结果表明,PaEXP1主要在根中表达,低温、盐、重金属和渗透胁迫均强烈地抑制其基因的表达.酵母转化实验表明,转PaEXP1可以提高酵母的平均直径,说明PaEXP1参与细胞壁的松弛扩展和细胞的增大过程.

With a full length cDNA of expansin,designed PaEXP1,was cloned in Phytolacca acinosa by the Homology-based cloning method.The PaEXP1 consisted of 1128 bp with an open reading frame of 759 bp that code a protein of 252 amino acids.Structural analysis showed that the eight cysteine residues and the HFD（His-Phe-Asp） sequence are near the N-terminal end,four tryptophan residues near the C-terminal end of predicted PaEXP1.The phylogenetic tree showed that PaEXP1 belonged to the α-expansion protein family.PaEXP1 was preferentially expressed in root.The expression of PaEXP1were strongly inhibited by various abiotic stress,such as the low temperature,salt,heavy metals and osmotic stress.The expression of PaEXP1 in yeast increased the average diameter of yeast,indicating PaEXP1 involved in cell wall expansion.