Abstract
The leukemogenic membrane glycoprotein of Friend spleen focus-forming virus (SFFV) has an apparent Mr of 55,000 (gp55), is encoded by a recombinant env gene, and occurs on cell surfaces and in intracellular organelles. There is evidence that the amino-terminal region of gp55 forms a dualtropic-specific domain that is connected to the remainder of the glycoprotein by a proline-rich linker (C. Machida, R. Bestwick, B. Boswell, and D. Kabat, Virology 144:158-172, 1985). Using the colinear form of a cloned polycythemic strain of SFFV proviral DNA, we constructed seven in-phase env mutants by insertion of linkers and by a deletion. The mutagenized SFFVs were transfected into fibroblasts and were rescued by superinfection with a helper murine leukemia virus. Four of the mutants cause erythroblastosis. These include one with a 6-base-pair (bp) insert in the ecotropic-related sequence near the 3' end of the gene, two with a 12- or 18-bp insert in the region that encodes the proline-rich linker, and one with a 6-bp insert in the dualtropic-specific region. The other mutants (RI, Sm1, and Sm2) are nonpathogenic and contain lesions in dualtropic-specific region. The other mutants (RI, Sm1, and Sm2) are nonpathogenic and contain lesions in dualtropic-specific sequences that are highly conserved among strains of SFFV. A pathogenic revertant (RI-rev) was isolated from one mouse that developed erythroblastosis 3 weeks after infection with RI. RI-rev contains a second-site env mutation that affects the same domain as the primary mutation does and that increases the size of the encoded glycoprotein. All pathogenic SFFVs encode glycoproteins that are expressed on cell surfaces, whereas the nonpathogenic glycoproteins are exclusively intracellular. The pathogenic SFFVs also specifically cause a weak interference to superinfection by dualtropic MuLVs. These results are compatible with the multidomain model for the structure of gp55 and suggest that processing of gp55 to plasma membranes is required for pathogenesis. The amino-terminal region of gp55 binds to dualtropic murine leukemia virus receptors, and this interaction is preserved in the SFFV mutants that cause erythroblastosis.
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- Adachi A., Sakai K., Kitamura N., Nakanishi S., Niwa O., Matsuyama M., Ishimoto A. Characterization of the env gene and long terminal repeat of molecularly cloned Friend mink cell focus-inducing virus DNA. J Virol. 1984 Jun;50(3):813–821. doi: 10.1128/jvi.50.3.813-821.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Amanuma H., Katori A., Obata M., Sagata N., Ikawa Y. Complete nucleotide sequence of the gene for the specific glycoprotein (gp55) of Friend spleen focus-forming virus. Proc Natl Acad Sci U S A. 1983 Jul;80(13):3913–3917. doi: 10.1073/pnas.80.13.3913. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bestwick R. K., Boswell B. A., Kabat D. Molecular cloning of biologically active Rauscher spleen focus-forming virus and the sequences of its env gene and long terminal repeat. J Virol. 1984 Sep;51(3):695–705. doi: 10.1128/jvi.51.3.695-705.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bestwick R. K., Hankins W. D., Kabat D. Roles of helper and defective retroviral genomes in murine erythroleukemia: studies of spleen focus-forming virus in the absence of helper. J Virol. 1985 Dec;56(3):660–664. doi: 10.1128/jvi.56.3.660-664.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burnette W. N. "Western blotting": electrophoretic transfer of proteins from sodium dodecyl sulfate--polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A. Anal Biochem. 1981 Apr;112(2):195–203. doi: 10.1016/0003-2697(81)90281-5. [DOI] [PubMed] [Google Scholar]
- Chesebro B., Wehrly K. Different murine cell lines manifest unique patterns of interference to superinfection by murine leukemia viruses. Virology. 1985 Feb;141(1):119–129. doi: 10.1016/0042-6822(85)90188-6. [DOI] [PubMed] [Google Scholar]
- Clark S. P., Mak T. W. Complete nucleotide sequence of an infectious clone of Friend spleen focus-forming provirus: gp55 is an envelope fusion glycoprotein. Proc Natl Acad Sci U S A. 1983 Aug;80(16):5037–5041. doi: 10.1073/pnas.80.16.5037. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clark S. P., Mak T. W. Fluidity of a retrovirus genome. J Virol. 1984 Jun;50(3):759–765. doi: 10.1128/jvi.50.3.759-765.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cone R. D., Mulligan R. C. High-efficiency gene transfer into mammalian cells: generation of helper-free recombinant retrovirus with broad mammalian host range. Proc Natl Acad Sci U S A. 1984 Oct;81(20):6349–6353. doi: 10.1073/pnas.81.20.6349. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dresler S., Ruta M., Murray M. J., Kabat D. Glycoprotein encoded by the Friend spleen focus-forming virus. J Virol. 1979 May;30(2):564–575. doi: 10.1128/jvi.30.2.564-575.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FRIEND C. Cell-free transmission in adult Swiss mice of a disease having the character of a leukemia. J Exp Med. 1957 Apr 1;105(4):307–318. doi: 10.1084/jem.105.4.307. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fasano O., Aldrich T., Tamanoi F., Taparowsky E., Furth M., Wigler M. Analysis of the transforming potential of the human H-ras gene by random mutagenesis. Proc Natl Acad Sci U S A. 1984 Jul;81(13):4008–4012. doi: 10.1073/pnas.81.13.4008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fitting T., Kabat D. Evidence for a glycoprotein "signal" involved in transport between subcellular organelles. Two membrane glycoproteins encoded by murine leukemia virus reach the cell surface at different rates. J Biol Chem. 1982 Dec 10;257(23):14011–14017. [PubMed] [Google Scholar]
- Fitting T., Kabat D. Protein A-coated erythrocyte binding to cell surface antigens: application to quantitate retrovirus infectivity in vitro. Virology. 1981 Jun;111(2):653–655. doi: 10.1016/0042-6822(81)90365-2. [DOI] [PubMed] [Google Scholar]
- Hankins W. D., Kost T. A., Koury M. J., Krantz S. B. Erythroid bursts produced by Friend leukaemia virus in vitro. Nature. 1978 Nov 30;276(5687):506–508. doi: 10.1038/276506a0. [DOI] [PubMed] [Google Scholar]
- Hankins W. D., Troxler D. Polycythemia- and anemia-inducing erythroleukemia viruses exhibit differential erythroid transforming effects in vitro. Cell. 1980 Dec;22(3):693–699. doi: 10.1016/0092-8674(80)90545-0. [DOI] [PubMed] [Google Scholar]
- Hartley J. W., Wolford N. K., Old L. J., Rowe W. P. A new class of murine leukemia virus associated with development of spontaneous lymphomas. Proc Natl Acad Sci U S A. 1977 Feb;74(2):789–792. doi: 10.1073/pnas.74.2.789. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hartley J. W., Yetter R. A., Morse H. C., 3rd A mouse gene on chromosome 5 that restricts infectivity of mink cell focus-forming recombinant murine leukemia viruses. J Exp Med. 1983 Jul 1;158(1):16–24. doi: 10.1084/jem.158.1.16. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kabat D., Ruta M., Murray M. J., Polonoff E. Immunoselection of mutants deficient in cell surface glycoproteins encoded by murine erythroleukemia viruses. Proc Natl Acad Sci U S A. 1980 Jan;77(1):57–61. doi: 10.1073/pnas.77.1.57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koch W., Hunsmann G., Friedrich R. Nucleotide sequence of the envelope gene of Friend murine leukemia virus. J Virol. 1983 Jan;45(1):1–9. doi: 10.1128/jvi.45.1.1-9.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koch W., Zimmermann W., Oliff A., Friedrich R. Molecular analysis of the envelope gene and long terminal repeat of Friend mink cell focus-inducing virus: implications for the functions of these sequences. J Virol. 1984 Mar;49(3):828–840. doi: 10.1128/jvi.49.3.828-840.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Li J. P., Bestwick R. K., Machida C., Kabat D. Role of a membrane glycoprotein in Friend virus erythroleukemia: nucleotide sequences of nonleukemogenic mutant and spontaneous revertant viruses. J Virol. 1986 Feb;57(2):534–538. doi: 10.1128/jvi.57.2.534-538.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Linemeyer D. L., Menke J. G., Ruscetti S. K., Evans L. H., Scolnick E. M. Envelope gene sequences which encode the gp52 protein of spleen focus-forming virus are required for the induction of erythroid cell proliferation. J Virol. 1982 Jul;43(1):223–233. doi: 10.1128/jvi.43.1.223-233.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Linemeyer D. L., Ruscetti S. K., Menke J. G., Scolnick E. M. Recovery of biologically active spleen focus-forming virus from molecularly cloned spleen focus-forming virus-pBR322 circular DNA by cotransfection with infectious type C retroviral DNA. J Virol. 1980 Sep;35(3):710–721. doi: 10.1128/jvi.35.3.710-721.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Linemeyer D. L., Ruscetti S. K., Scolnick E. M., Evans L. H., Duesberg P. H. Biological activity of the spleen focus-forming virus is encoded by a molecularly cloned subgenomic fragment of spleen focus-forming virus DNA. Proc Natl Acad Sci U S A. 1981 Mar;78(3):1401–1405. doi: 10.1073/pnas.78.3.1401. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Machida C. A., Bestwick R. K., Boswell B. A., Kabat D. Role of a membrane glycoprotein in Friend virus-induced erythroleukemia: studies of mutant and revertant viruses. Virology. 1985 Jul 15;144(1):158–172. doi: 10.1016/0042-6822(85)90314-9. [DOI] [PubMed] [Google Scholar]
- Machida C. A., Bestwick R. K., Kabat D. A weakly pathogenic Rauscher spleen focus-forming virus mutant that lacks the carboxyl-terminal membrane anchor of its envelope glycoprotein. J Virol. 1985 Mar;53(3):990–993. doi: 10.1128/jvi.53.3.990-993.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Machida C. A., Bestwick R. K., Kabat D. Reduced leukemogenicity caused by mutations in the membrane glycoprotein gene of Rauscher spleen focus-forming virus. J Virol. 1984 Feb;49(2):394–402. doi: 10.1128/jvi.49.2.394-402.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mann R., Mulligan R. C., Baltimore D. Construction of a retrovirus packaging mutant and its use to produce helper-free defective retrovirus. Cell. 1983 May;33(1):153–159. doi: 10.1016/0092-8674(83)90344-6. [DOI] [PubMed] [Google Scholar]
- Messing J. New M13 vectors for cloning. Methods Enzymol. 1983;101:20–78. doi: 10.1016/0076-6879(83)01005-8. [DOI] [PubMed] [Google Scholar]
- Miller A. D., Law M. F., Verma I. M. Generation of helper-free amphotropic retroviruses that transduce a dominant-acting, methotrexate-resistant dihydrofolate reductase gene. Mol Cell Biol. 1985 Mar;5(3):431–437. doi: 10.1128/mcb.5.3.431. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Murray M. J., Kabat D. Genetic and sialylation sources of heterogeneity of the murine leukemia virus membrane envelope glycoproteins gp69/71. J Biol Chem. 1979 Feb 25;254(4):1340–1348. [PubMed] [Google Scholar]
- Peebles P. T. An in vitro focus-induction assay for xenotropic murine leukemia virus, feline leukemia virus C, and the feline--primate viruses RD-114/CCC/M-7. Virology. 1975 Sep;67(1):288–291. doi: 10.1016/0042-6822(75)90427-4. [DOI] [PubMed] [Google Scholar]
- Pinter A., Honnen W. J. The mature form of the Friend spleen focus-forming virus envelope protein, gp65, is efficiently secreted from cells. Virology. 1985 Jun;143(2):646–650. doi: 10.1016/0042-6822(85)90406-4. [DOI] [PubMed] [Google Scholar]
- ROWE W. P., BRODSKY I. A graded-response assay for the Friend leukemia virus. J Natl Cancer Inst. 1959 Dec;23:1239–1248. [PubMed] [Google Scholar]
- Rein A. Interference grouping of murine leukemia viruses: a distinct receptor for the MCF-recombinant viruses in mouse cells. Virology. 1982 Jul 15;120(1):251–257. doi: 10.1016/0042-6822(82)90024-1. [DOI] [PubMed] [Google Scholar]
- Rein A., Schultz A. Different recombinant murine leukemia viruses use different cell surface receptors. Virology. 1984 Jul 15;136(1):144–152. doi: 10.1016/0042-6822(84)90255-1. [DOI] [PubMed] [Google Scholar]
- Ruscetti S. K., Feild J. A., Scolnick E. M. Polycythaemia- and anaemia-inducing strains of spleen focus-forming virus differ in post-translational processing of envelope-related glycoproteins. Nature. 1981 Dec 17;294(5842):663–665. doi: 10.1038/294663a0. [DOI] [PubMed] [Google Scholar]
- Ruscetti S. K., Linemeyer D., Feild J., Troxler D., Scolnick E. M. Characterization of a protein found in cells infected with the spleen focus-forming virus that shares immunological cross-reactivity with the gp70 found in mink cell focus-inducing virus particles. J Virol. 1979 Jun;30(3):787–798. doi: 10.1128/jvi.30.3.787-798.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ruscetti S., Davis L., Feild J., Oliff A. Friend murine leukemia virus-induced leukemia is associated with the formation of mink cell focus-inducing viruses and is blocked in mice expressing endogenous mink cell focus-inducing xenotropic viral envelope genes. J Exp Med. 1981 Sep 1;154(3):907–920. doi: 10.1084/jem.154.3.907. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ruscetti S., Wolff L. Biological and biochemical differences between variants of spleen focus-forming virus can be localized to a region containing the 3' end of the envelope gene. J Virol. 1985 Dec;56(3):717–722. doi: 10.1128/jvi.56.3.717-722.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ruta M., Bestwick R., Machida C., Kabat D. Loss of leukemogenicity caused by mutations in the membrane glycoprotein structural gene of Friend spleen focus-forming virus. Proc Natl Acad Sci U S A. 1983 Aug;80(15):4704–4708. doi: 10.1073/pnas.80.15.4704. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ruta M., Clarke S., Boswell B., Kabat D. Heterogeneous metabolism and subcellular localization of a potentially leukemogenic membrane glycoprotein encoded by Friend erythroleukemia virus. Isolation of viral and cellular processing mutants. J Biol Chem. 1982 Jan 10;257(1):126–134. [PubMed] [Google Scholar]
- Ruta M., Kabat D. Plasma membrane glycoproteins encoded by cloned Rauscher and Friend spleen focus-forming viruses. J Virol. 1980 Sep;35(3):844–853. doi: 10.1128/jvi.35.3.844-853.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shimizu K., Goldfarb M., Suard Y., Perucho M., Li Y., Kamata T., Feramisco J., Stavnezer E., Fogh J., Wigler M. H. Three human transforming genes are related to the viral ras oncogenes. Proc Natl Acad Sci U S A. 1983 Apr;80(8):2112–2116. doi: 10.1073/pnas.80.8.2112. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stone J. C., Atkinson T., Smith M., Pawson T. Identification of functional regions in the transforming protein of Fujinami sarcoma virus by in-phase insertion mutagenesis. Cell. 1984 Jun;37(2):549–558. doi: 10.1016/0092-8674(84)90385-4. [DOI] [PubMed] [Google Scholar]
- Tabin C. J., Bradley S. M., Bargmann C. I., Weinberg R. A., Papageorge A. G., Scolnick E. M., Dhar R., Lowy D. R., Chang E. H. Mechanism of activation of a human oncogene. Nature. 1982 Nov 11;300(5888):143–149. doi: 10.1038/300143a0. [DOI] [PubMed] [Google Scholar]
- Troxler D. H., Lowy D., Howk R., Young H., Scolnick E. M. Friend strain of spleen focus-forming virus is a recombinant between ecotropic murine type C virus and the env gene region of xenotropic type C virus. Proc Natl Acad Sci U S A. 1977 Oct;74(10):4671–4675. doi: 10.1073/pnas.74.10.4671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wolff L., Kaminchik J., Hankins W. D., Ruscetti S. K. Sequence comparisons of the anemia- and polycythemia-inducing strains of Friend spleen focus-forming virus. J Virol. 1985 Feb;53(2):570–578. doi: 10.1128/jvi.53.2.570-578.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wolff L., Koller R., Ruscetti S. Monoclonal antibody to spleen focus-forming virus-encoded gp52 provides a probe for the amino-terminal region of retroviral envelope proteins that confers dual tropism and xenotropism. J Virol. 1982 Aug;43(2):472–481. doi: 10.1128/jvi.43.2.472-481.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wolff L., Ruscetti S. Malignant transformation of erythroid cells in vivo by introduction of a nonreplicating retrovirus vector. Science. 1985 Jun 28;228(4707):1549–1552. doi: 10.1126/science.2990034. [DOI] [PubMed] [Google Scholar]
- Wolff L., Scolnick E., Ruscetti S. Envelope gene of the Friend spleen focus-forming virus: deletion and insertions in 3' gp70/p15E-encoding region have resulted in unique features in the primary structure of its protein product. Proc Natl Acad Sci U S A. 1983 Aug;80(15):4718–4722. doi: 10.1073/pnas.80.15.4718. [DOI] [PMC free article] [PubMed] [Google Scholar]