SELECTIVE EXPRESSION OF A SUBSET OF MEASLES-VIRUS RECEPTOR-COMPETENT CD46 ISOFORMS IN HUMAN BRAIN

The human cell surface protein CD46 is the main measles virus (MV) rec eptor. We analyzed the CD46 isoforms expressed in the brain of three p atients who died with persistent MV infections and in an unaffected br ain. Complete CD46 cDNAs were produced and found to code exclusively f or CD46 isoforms with cytoplasmic tail 2. Selective expression of tail 2 isoforms was shown in a second control brain by Western blots with antibodies specific for each of the cytoplasmic tails. Binding of puri fied MV particles and virus-dependent cell fusion were tested after tr ansient expression of brain-derived CD46 proteins in mouse cells. All the brain-derived proteins mediated MV binding and virus-dependent fus ion. Isoforms containing both serine/threonine/proline (STP)-rich doma ins were more active in virus binding, whereas isoforms with only one STP domain were more efficient in mediating fusion. (C) 1996 Academic Press, Inc.