In Friend erythroleukemia, the membrane glycoprotein (gp55) encoded by Friend spleen focus-forming virus (SFFV) binds as an agonist to murine erythropoietin receptors (EpoR) to stimulate erythroblastosis. We recently cloned the human Epo gene and produced helper-free retrovirions that encode Epo, murine EpoR or gp55. Coinfection of murine IL-3 dependent cells with the EpoR virus plus either of the other viruses was able to convert the cells to factor-independent proliferation. Interestingly, erythroblasts of mice homozygous for Fv-2r have severely reduced mitogenic response to Epo; and these mice are therefore resistant to both Friend and to Epo virus- induced erythroleukemias. Mapping indicated that EpoR and Fv-2 genes are unlinked. We proposed: (1) Use genetic and biochemical methods to analyze Fv-2 role in EpoR signal transduction. Does Fv-2 encode a second EpoR subunit or a transducin? Molecularly clone Fv-2. (2) Friend erythroleukemia is considered restricted to mice. Why? Cannot gp55 bind to nonmurine EpoR? Or, do other species have an Fv-2rr-like phenotype? Clone human EpoR. Analyze mitogenic interactions of gp55 and Epo with human and murine EpoR in factor-dependent cells from humans or mice. (3) Use methods including mutagenesis to identify active sites for binding and mitogenesis on Epo and EpoR. (4) Produce a soluble derivative of EpoR in substantial amounts. Study Epo-sEpoR interaction by physical methods including cocrystallization and X-ray diffraction. Use sEpoR for a sensitive Epo assay. Does sEpoR cure Friend erythroleukemia? (5) Analyze EpoR processing and mitogenic signalling. This project is important for understanding hematopoietic growth factor receptors in leukemias and it provides a unique model for learning at the molecular level how host genetic variation (e.g., Fv-2) controls susceptibility to an oncogenic protein.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA054149-03
Application #
3198623
Study Section
Experimental Virology Study Section (EVR)
Project Start
1991-04-01
Project End
1995-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
3
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Oregon Health and Science University
Department
Type
Schools of Dentistry
DUNS #
009584210
City
Portland
State
OR
Country
United States
Zip Code
97239
Marin, M; Tailor, C S; Nouri, A et al. (1999) Polymorphisms of the cell surface receptor control mouse susceptibilities to xenotropic and polytropic leukemia viruses. J Virol 73:9362-8
Tailor, C S; Nouri, A; Lee, C G et al. (1999) Cloning and characterization of a cell surface receptor for xenotropic and polytropic murine leukemia viruses. Proc Natl Acad Sci U S A 96:927-32
Siciliano, S J; Kuhmann, S E; Weng, Y et al. (1999) A critical site in the core of the CCR5 chemokine receptor required for binding and infectivity of human immunodeficiency virus type 1. J Biol Chem 274:1905-13
Hoatlin, M E; Gomez-Lucia, E; Lilly, F et al. (1998) Origin and rapid evolution of a novel murine erythroleukemia virus of the spleen focus-forming virus family. J Virol 72:3602-9
Gomez-Lucia, E; Zhi, Y; Nabavi, M et al. (1998) An array of novel murine spleen focus-forming viruses that activate the erythropoietin receptor. J Virol 72:3742-50
Hoatlin, M E; Kabat, D (1995) Host-range control of a retroviral disease: Friend erythroleukemia. Trends Microbiol 3:51-7
Hoatlin, M E; Kozak, S L; Spiro, C et al. (1995) Amplified and tissue-directed expression of retroviral vectors using ping-pong techniques. J Mol Med 73:113-20
Hoatlin, M E; Ferro Jr, F E; Kozak, S L et al. (1994) A Friend virus mutant encodes a small glycoprotein that causes erythroleukemia. J Virol 68:4053-6
Ferro Jr, F E; Kozak, S L; Hoatlin, M E et al. (1993) Cell surface site for mitogenic interaction of erythropoietin receptors with the membrane glycoprotein encoded by Friend erythroleukemia virus. J Biol Chem 268:5741-7
Kozak, S L; Hoatlin, M E; Ferro Jr, F E et al. (1993) A Friend virus mutant that overcomes Fv-2rr host resistance encodes a small glycoprotein that dimerizes, is processed to cell surfaces, and specifically activates erythropoietin receptors. J Virol 67:2611-20