A study of the relationship of reticuloendotheliosis virus to the avion leukosis-sarcoma complex of viruses

Abstract

Reticuloendotheliosis virus (REV) was compared on biological and biochemical grounds with members of the avian leukosis-sarcoma complex of viruses (ALSV). Stocks of REV contained no virus which produced interference with any subgroup of ALSV. REV was unable to complement various strains of Rous sarcoma virus (RSV) as measured by the absence of broadening of host range, “helper” virus activity with the defective Bryan high titer strain of RSV, or the induction of release of RAV-60 from chick embryo cells containing the chick helper factor. Hence, no biological interaction has been detected between REV and the avian leukosis-sarcoma complex of viruses. The RNA structure of the REV was studied using glycerol velocity gradients and polyacrylamide gel electrophoresis. The RNA of REV was distinctly like that of RAV-49, a subgroup C avian leukosis virus. The native RNA of REV recovered after phenol extraction cosedimented with the RNA of RAV-49, and after heat denaturation, both RNAs showed the reduced sedimentation velocity and increased rate of migration in polyacrylamide gel which is characteristic of the tumor virus RNAs. Proteins of REV were examined on SDS discontinuous gel electrophoresis. Five major proteins were detected, two of which were glycoproteins. Coelectrophoresis of REV with avian sarcoma virus B 77 showed no polypeptides that were identical in electrophoretic mobilities. In addition, lactoperoxidase catalyzed iodination was employed to selectively label the surface proteins of REV. Two surface proteins were detected; these corresponded to the two viral glycoproteins.