光皮树SwFAD7基因克隆及其表达研究

Cloning and Expression Gene SwFAD7 in Cornus Wilsoniana

为了获得光皮树脂肪酸去饱和酶合成的关键基因,本研究以光皮树未成熟种子为材料克隆FAD7基因,并利用q PCR技术分析果实发育过程中FAD7基因表达量变化。结果表明:光皮树FAD7基因(Sw FAD7)编码区长1 800 bp,推测编码448个氨基酸,相对分子质量51.29 k D,等电点7.14,具有三个跨膜结构域。Sw FAD7基因所编码的蛋白质含有FAD蛋白家族所特有四个富含组氨酸的保守区域。Sw FAD7蛋白的二级结构组要由α-螺旋和无规则卷曲构成,蛋白质中均夹杂分布着β-折叠。系统进化树分析表明Sw FAD7单独形成一个分支。对未成熟果实中Sw FAD7基因表达分析表明,该基因在7~8月间呈现先上升后下降再上升的表达变化趋势,于7月23日左右达到累积的最高点。

In order to obtain the key gene in linolenic acid formation way in cornus wilsoniana, the immature fruits were used to clone FAD7 gene, and q PCR technology was used to analyze the FAD7 gene expression changes in the process of fruit development. FAD7 gene(named Sw FAD7) was cloned from cornus wilsoniana using RACE strategy. The c DNA of Sw FAD7 is 1 800 bp in length which presumably code 448 amino acids. Its MW(molecular weight) is 51.29 k D with the isoelectric point 7.14, and it has three across membrane structure.The protein coded by Sw FAD7 gene contains the unique four conservative histidine-rich regions which is an important feature in FAD gene family. The α-helixs and random coils are the main structural components of its secondary structure, while β-sheets spread in the whole protein. The phylogenetic tree analysis showed that the genetic relationship of Sw FAD7 is separated as an independent branch. The result of Sw FAD7 gene expression in immature fruit showed that the gene expression present as increase-decrease-increase pattern from July to August, with the highest point at July 23.