RNA-dependent DNA polymerase associated with equine infectious anemia virus

Abstract

Equine infectious anemia (EIAV) has an associated RNA-instructed DNA polymerase similar in its cofactor requirements and reaction conditions to the RNA tumor virus DNA polymerases. Demonstrating this DNA polymerase activity requires a critical concentration of a nonionic detergent, all 4 deoxyribonucleoside triphosphates and a divalent metal ion. The reaction is sensitive to RNase, and a substantial fraction of the DNA synthesized is complementary to viral RNA. The detection of a complex of 3H-labeled polymerase product DNA-template RNA, which sedimented at 60-70S, indicated that EIAV contains high-MW RNA. These results, obtained with virus propagated in [equine fibroblast] cell culture and virus from the serum of an experimentally infected horse, indicate that EIAV may properly be considered a member of the family Retroviridae. They may also be pertinent to the mechanism(s) of viral persistence and periodic recrudescence of disease in chronically infected horses.