title: An avian leukosis virus subgroup J isolate with a Rous sarcoma virus-like 5'-LTR shows enhanced replication capability.
abstract: Avian leukosis virus subgroup J (ALV-J) was first isolated from meat-producing chickens that had developed myeloid leukosis. However, ALV-J infections associated with hemangiomas have occurred in egg-producing (layer) flocks in China. In this study, we identified an ALV-J layer isolate (HLJ13SH01) as a recombinant of ALV-J and a Rous sarcoma virus Schmidt-Ruppin B strain (RSV-SRB), which contained the RSV-SRB 5'-LTR and the other genes of ALV-J. Replication kinetic testing indicated that the HLJ13SH01 strain replicated faster than other ALV-J layer isolates in vitro. Sequence analysis indicated that the main difference between the two isolates was the 5'-LTR sequences, particularly the U3 sequences. A 19 nt insertion was uniquely found in the U3 region of the HLJ13SH01 strain. The results of a Dual-Glo luciferase assay revealed that the 19 nt insertion in the HLJ13SH01 strain increased the enhancer activity of the U3 region. Moreover, an additional CCAAT/enhancer element was found in the 19 nt insertion and the luciferase assay indicated that this element played a key role in increasing the enhancer activity of the 5'-U3 region. To confirm the potentiation effect of the 19 nt insertion and the CCAAT/enhancer element on virus replication, three infectious clones with 5'-U3 region variations were constructed and rescued. Replication kinetic testing of the rescued viruses demonstrated that the CCAAT/enhancer element in the 19 nt insertion enhanced the replication capacity of the ALV-J recombinant in vitro.
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Yanni
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Guan
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Li
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Bingling
authors.initials: B
authors.lastname: Yun
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Xiaole
authors.initials: X
authors.lastname: Qi
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Honglei
authors.initials: H
authors.lastname: Gao
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Cui
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Changjun
authors.initials: C
authors.lastname: Liu
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, PR China.|Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Gao
mesh_terms: D000818:Animals; D001353:Avian Leukosis / Q000821:virology*; D001354:Avian Leukosis Virus / Q000235:genetics*; D002645:Chickens / Q000821:virology*; D002681:China; D004261:DNA Replication / Q000235:genetics*; D011201:Poultry Diseases / Q000821:virology*; D052736:Rous sarcoma virus / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics*