PROPERTIES OF A UNIQUE FORM OF THE MURINE AMPHOTROPIC LEUKEMIA-VIRUS RECEPTOR EXPRESSED ON HAMSTER-CELLS

Identification and cloning of the receptors for amphotropic murine leu kemia virus (A-MuLV) and gibbon ape leukemia virus (GaLV) have both en abled the determination of the normal function of these virus receptor s in cells and initiated experimental examination of how these recepto rs interact with their respective viruses. GaLV and A-MuLV have distin ct host ranges and use different receptors to infect human cells. It w as therefore surprising to find that the human GaLV and A-MuLV recepto rs were not only structurally similar but performed similar cellular f unctions (B. O'Hara, S. V. Johann, H. P. Klinger, D. G. Flair, H. Rubi nson, K. J. Dunn, P. Sass, S. M. Vitek, and T. Robbins, Cell Growth Di ffer. 1:119-127, 1990; M. van Zeijl, S. V. Johann, E. Closs, J. Cunnin gham, R. Eddy, T. B. Shows, and B. O'Hara, Proc. Natl. Acad. Sci. USA 91:1168-1172, 1994; M. P. Kavanaugh, D. G. Miller, W. Zhang, W. Law, S . L. Kozak, D. Kabat, and A. D. Miller, Proc. Natl. Acad. Sci. USA 91: 7071-7075, 1994; and Z. Olah, C. Lehel, W. B. Anderson, M. V. Eiden, a nd C. A. Wilson, J. Biol. Chum., in press). We have now determined tha t the murine retrovirus 10A1 can use both the human GaLV receptor and the human A-MuLV receptor to infect cells. Furthermore, we have cloned and functionally characterized a unique form of the amphotropic recep tor homolog expressed in E36 hamster cells. This receptor (EAR) can se rve as both a GaLV receptor and an A-MuLV receptor, and it therefore d iffers from the receptors expressed in human cells, which function exc lusively as either GaLV or A-MuLV receptors.