Glycopeptides of murine leukemia viruses. II. Comparison of xenotropic and dual-tropic viruses

Abstract

The glycosylation patterns of the gp70 glycoproteins of xenotropic and dualtropic murine leukemia virus (MuLV) were compared with those of ecotropic viruses. Ecotropic viruses contain a large glycopeptide size class designated G1 (molecular weight, approximately 5100), and such glycopeptides were not detected in xenotropic viruses grown in mink cells nor in dual-tropic viruses grown in mouse or mink lung cells. Both xenotropic and dual-tropic MuLV had glycopeptide size classes designated G2, G3, and G4 (molecular weights, approximately 2900, 2,200, and 1,500, respectively). G2 glycopeptides of xenotropic and dual-tropic MuLV were shown to be resistant to endo-beta-N-acetylglucosaminidase H, whereas G3 and G4 glycopeptides were susceptible. The relative abudance of glycopeptide G3 was increased in xenotropic and dual-tropic viruses as compared with ecotropic viruses, whereas the relative amount of G4 was decreased in xenotropic viruses. The similarity in the glycosylation patterns of a number of xenotropic and dual-tropic viruses suggests that glycosylation sites are highly conserved within the env gene products of each of these classes of viruses.

Nucleotide sequence of the envelope gene of Friend murine leukemia virus

“…products are highly conserved in the different host range classes of murine retroviruses (25,26). Eight such sites were found in the amino acid sequence of F-MuLV gp7O (Fig.…”

Glycopeptides of Murine Leukemia Viruses III. Glycosylation of env Precursor Glycoproteins

“…It has been demonstrated previously that gp7O's of MuLV's from different host range classes (7, 8, 15), as well as avian retrovirus glycoproteins (6), possess both mannose-rich and complex oligosaccharide side chains. The patterns of glycosylation observed for gp7O's of MuLV's were distinctive for members of different host range classes, were constant for several viruses from each class, and were not altered significantly when viruses were grown in different host cells (8). These findings suggested that the structure of the gp7O oligosaccharides is determined by the polypeptide backbone and that glycosylation sites on this molecule are conserved within each host range class.…”

“…Virus and cells. The origins of the viruses used have been previously described (8). Virus producer cell lines in either mouse fibroblasts (SC-1) or mink lung fibroblasts (CCL64) were provided by P. V. O'Donnell, Memorial Sloan-Kettering Cancer Center.…”

“…Preparation and analysis of glycopeptides. Gel segments containing the radiolabeled glycoproteins were rehydrated, and the glycopeptides were prepared by pronase digestion as described previously (8) and chromatographed on Bio-Gel P-6 with ["4C]glucosamine-labeled A/WSN(HON1) influenza virus marker glycopeptides (11).…”

“…The endo-H-treated env gene products were then analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis as described above. tides of a number of MuLV's from different host range classes, we have demonstrated that the gp7O's from the different host range classes have distinguishable glycosylation patterns (8). To determine if the oligosaccharides linked to the PrENV proteins also exhibited such differences, we analyzed the glycopeptides of PrENV proteins coded for by ecotropic, xenotropic, and dual-tropic MuLV's.…”