大腹圆蛛拖丝蛋白基因3′端克隆和序列分析

The Cloning and Sequence Analysis of Araneus Ventricosus Dragline Silk Protein Gene 3' Flanking

用PCR(Polymerase Chain Reaction)技术从大腹圆蛛主壶腹腺组织的基因组DNA和RNA中分别扩增获得编码拖丝蛋白基因的3′端基因序列,克隆PCR产物到pDrive载体,经PCR、限制性酶切筛选和序列分析后证明获得了蜘蛛拖丝蛋白基因两个克隆AvDS1和AvRS2.基因序列和氨基酸序列分析表明AvDS1和AvRS2具有拖丝蛋白基因序列和蛋白质氨基酸序列特有的结构特征,氨基酸序列中存在4个motifs—(A)n,(GA)n,(GPGX)n以及(GGX)n.AvDS1与基因库中已报道的蜘蛛拖丝蛋白基因序列同源性较低,而AvRS2与已经报道的Nephila clavipes拖丝蛋白基因组分-1的同源性可达91%,推测AvRS2是编码大腹圆蛛拖丝蛋白基因组分-1基因片段.比较这两个克隆的核苷酸序列和氨基酸序列,发现它们之间没有同源性.推测它们是同一基因的不同片段,或是编码大腹圆蛛拖丝蛋白的两个基因组分.

The spider dragline silk protein gene 3＇ flanking sequences, amplifed by PCR and RT-PCR from the special gland named major ampulate （MA） gland, were cloned into pDrive vector. The recombinant plasmids, named AvDS1 and AvRS2, were sequenced. Predicted amino acid sequence of AvDS1 and AvRS2 clones indicated that the inserts were composed of numerous iterations of four different amino acid motifs--（A）n, （GA）n, （GPGX）n, and （GGX）n. The homologous sequence of AvDS1 DNA was very low with dragline silk protein gene coming from others reported after sequence analyzing, but, was up to 91% between AvRS2 and Nephila clavipes＇ fibroin protein gene. AvRS2 was presumed to be different parts of fibroin protein gene or another dragline silk protein gene.