【摘要】 为对犬干扰素-β(IFN-β)进行研究,用PCR技术从犬血细胞基因组DNA中扩增了牧羊犬IFN-β基因,并克隆到pGEM-T载体,转化大肠杆菌JM109感受态细胞,阳性克隆经PCR和酶切鉴定后进行测序。结果表明:牧羊犬IFN-β基因含561bp,编码186个氨基酸,前21个为信号肽。成熟蛋白理论分子量为20kD,等电点为5.737,有2个潜在磷酸化位点、5个N糖基化位点和4个半胱氨酸残基,大部分为亲水区。二、三级结构预测显示,蛋白主要由5段α螺旋组成。犬IFN-β基因与赤狐的完全相同,与貉、雪貂和猫的同源性很高(85%～98.4%),在进化树中处于同一分支,而与禽类和鱼类的同源性仅为2.9%～8.6%。更多还原

【Abstract】 The interferon-β(IFN-β) gene of shepherd dog was amplified by PCR from genome DNA of blood cell,then cloned into pGEM-T easy vector and transformed into the competent cell of E.coli JM109.The positive clone was sequenced after identification of restriction endonuclease cleavage and PCR amplification.Shepherd dog IFN-β consisted of 561 bp and coded for 186 amino acids of which the first 21 amino acids constituted a putative signal peptide.The mature protein with the predicted molecular weight of 21 kD and the isoelectric point of 5.737 contained 2 potential casein kinase II phosphorylation sites,5 N-glycosylation sites and 4 cysteines,and most of which were hydrophilic region.The protein mainly composed of 5 α-helix domains according to the secondary and tertiary structure prediction.The IFN-β gene of shepherd dog was identity to that of red fox and shared high homology of 85 %-98.4 % with raccoon dog,ferret and domestic cat.They grouped into the same branche in the phylogenetic tree base on IFN-β gene.更多还原