The unique envelope gene of the subgroup J avian leukosis virus derives from ev/J proviruses, a novel family of avian endogenous viruses.
A new subgroup of avian leukosis virus (ALV), designated subgroup J, was identified recently. Viruses of this subgroup do not cross-interfere with viruses of the avian A, B, C, D, and E subgroups, are not neutralized by antisera raised against the other virus subgroups, and have a broader host range than the A to E subgroups. Sequence comparisons reveal that while the subgroup J envelope gene includes some regions that are related to those found in env genes of the A to E subgroups, the majority of the subgroup J gene is composed of sequences either that are more similar to those of a member (E51) of the ancient endogenous avian virus (EAV) family of proviruses or that appear unique to subgroup J viruses. These data led to the suggestion that the ALV-J env gene might have arisen by multiple recombination events between one or more endogenous and exogenous viruses. We initiated studies to investigate the origin of the subgroup J envelope gene and in particular to determine the identity of endogenous sequences that may have contributed to its generation. Here we report the identification of a novel family of avian endogenous viruses that include env coding sequences that are over 95% identical to both the gp85 and gp37 coding regions of subgroup J viruses. We call these viruses the ev/J family. We also report the isolation of ev/J-encoded cDNAs, indicating that at least some members of this family are expressed. These data support the hypothesis that the subgroup J envelope gene was acquired by recombination with expressed endogenous sequences and are consistent with acquisition of this gene by only one recombination event.
Benson
S J
SJ
Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
Ruis
B L
BL
Fadly
A M
AM
Conklin
K F
KF
D000595:Amino Acid Sequence; D000818:Animals; D001354:Avian Leukosis Virus / Q000145:classification* / Q000235:genetics*; D001483:Base Sequence; D002645:Chickens; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D020077:Endogenous Retroviruses / Q000235:genetics*; D015752:Genes, env; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011533:Proviruses / Q000235:genetics*; D011995:Recombination, Genetic; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D017931:DNA Primers; D004279:DNA, Viral