禽白血病病毒J亚群env基因的克隆和序列分析

应用多聚酶链反应（PCR）的方法增出ADOL－4817毒株的囊膜蛋白env基因，并克隆进大肠杆菌。经核酸序列分析证明，env基因的大小为1746bp，其中gp85和gp37mh 1554bp组成，可翻译成517个氨基酸，分子量为57.7kD。根据糖基化位点N－X－S／T的特点，发现ADOL－4817的env蛋白有15个潜在的糖基化位点。同源性分析证明，ADOL－4817的env基因与其它ALV－J的env基因序列同源性为88.8％－92.4%，而与外源性ALVs的相应序列的同源性仅为40.5％－51.4％，然而，与内源性的EAV－HP毒株的类env基因的同源性高达91.2％；另外，ADOL－4817毒株的gp37d C末端多了13个氨基酸，这些结果提示，ALV－J的env基因存在广泛的变异性，env基因可能来源于内源性和外源性ALVs的重组。

Cloning and Sequencing of Envelope Gene of Subgroup J Avian Leukosis Virus

The envelope gene of ADOL 4817 strain of avian leukosis virus subgroup J (ALV J) was amplified by polymerase chain reaction (PCR) and cloned into TA vector. The sequence analysis results showed that the envelope gene is composed of 1?746 bp, 1?554 bp of which could be translated into 517 amino acids for gp85 and gp37. The molecular weight of envelope protein is 57.7kD. There are 15 potential glycosylation sites in the envelope protein, 13 of which is located in gp85. Analysis of sequences of envelope gene indicate that ADOL 4817 showed high degree of sequence identity to other ALV J strains, and most closely related to the like envelope gene of endogenous virus EAV HP but divergent from these of other ALV subgroup A E . These data support the hypothesis that envelope gene of avian leukosis virus subgroup J maybe acquired by recombination with expressed sequences.