Vaccinia Virus Semaphorin Grant McFadden1,* and Richard Moyer2 1 The John P. Robarts Research Institute and Department of Microbiology and Immunology, The University of Western Ontario, 1400 Western Road, London, Ontario, N6G 2V4, Canada 2 Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, PO Box 100266, Gainesville, FL 32610-0266, USA * corresponding author tel: (519)663-3184, fax: (519)663-3847, e-mail:
[email protected] DOI: 10.1006/rwcy.2000.03019. SUMMARY Structure Certain poxviruses express a member of the semaphorin superfamily, which are a large group of cellular proteins that were first characterized in nervous tissue as regulators of guidance of sensory neurons, but members probably have immunomodulatory roles as well. The vaccinia virus semaphorin is encoded by the A39R gene (in strain Copenhagen) and is expressed as a secreted protein that binds to a cellular receptor called VESPR (virus-encoded semaphorin protein receptor), but the biological role of this protein has yet to be defined. A39R is a contiguous gene lacking introns. BACKGROUND Discovery Supernates from cells infected with vaccinia vi