Measles virus fusion: role of the cysteine-rich region of the fusion glycoprotein.

Measles virus (MV) fusion requires the participation of both the fusion (F) and hemagglutinin (H) glycoproteins. The canine distemper virus fusion protein (CDVF) cannot substitute for the measles virus fusion protein (MVF) in this process. Introduction of restriction enzyme sites into the cDNAs of CDVF and MVF by site-directed mutagenesis facilitated the production of chimeric F proteins which were tested for their capacity to give fusion when coexpressed with MVH. Fusion resulted when the amino-terminal half of the MVF cysteine-rich region was transferred to CDVF.