China Animal Husbandry and Veterinary Medicine ›› 2019, Vol. 46 ›› Issue (9): 2683-2690.doi: 10.16431/j.cnki.1671-7236.2019.09.023

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Cloning and Sequence Analysis of env Gene of ALV Guizhou Strain

HE Ling1,2, YANG Qiuming1,2, YUAN Haiwen1,2, YANG Yuan1,2, WEN Guilan1,2, CHENG Zhentao1,2   

  1. 1. College of Animal Science, Guizhou University, Guiyang 550025, China;
    2. Key Laboratory of Animal Health and Veterinary Public Health, Guizhou Province, Guiyang 550025, China
  • Received:2019-01-25 Online:2019-09-20 Published:2019-09-21

Abstract: In order to understand the genetic variation and molecular characteristics of avian leukaemia virus (ALV) endemic strains in Guizhou,this study designed and synthesized primers based on ALV env gene for the purpose of gene amplification,cloning and sequence analysis of avian leukaemia clinical cases.The results showed that 3 positive samples were selected from clinical cases.The target gene fragments with a size of 921 bp were obtained by PCR amplification and named as GZ-ALV-1,GZ-ALV-2 and GZ-ALV-3 strains.Sequence analysis results showed that the nucleotide homology of 3 ALV epidemic strains in Guizhou ranged from 97.2% to 97.6%,which was relatively high with ALV-J at home and abroad,ranging from 93.1% to 99.3%,while the homology with ALV subgroups A,B,C,D,E and K was only 51.4% to 53.2%.The phylogenetic tree analysis showed that 3 ALV epidemic strains in Guizhou were in the same branch as the reference strains of ALV-J subgroup,which further indicated that all the ALV strains detected in this paper were ALV-J subgroup,while in different branches compared with A,B,C,D,E and K subgroups.The gene mutation analysis showed that 37 same nucleotide mutations of 3 epidemic strains resulted in 17 amino acid mutation sites,including 9 variable points in the high-variable region of hr1 and hr2,and 1 variable point in the low-variable region of vr3.The results showed that 3 ALV strains in Guizhou were ALV-J subgroup,and env gene loci were mutated,and the variable loci were located in the high-variable region.The results provided basic data for the epidemic situation of avian leukemia and the prevention and control and purification of ALV in Guizhou province.

Key words: avian leukosis virus (ALV); env gene; cloning; sequence analysis

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