The cleavage activation and sites of glycosylation in the fusion protein of Hendra virus

Hendra virus (HeV) is an unclassified member of the Paramyxoviridae family that causes systemic infections in humans, horses, cats, guinea pigs and fl ying foxes. The fusion protein (F-0) of members of the Paramyxoviridae fami ly that cause systemic infections in vivo contains a basic amino acid-rich region at which the protein is activated by cleavage into two subunits (F-1 and F-2). HeV F-0 lacks such a domain. We have determined the cleavage sit e in HeV F-0 by sequencing the amino terminus of the F-1 subunit and in vie w of the potential effect of glycosylation on the cleavage process have asc ertained the sites at which F-0 is glycosylated. The results indicate that unlike other members of the family that replicate in cultured cells and cau se systemic infections in vivo, cleavage of HeV F-0 occurs at a single lysi ne (reside 109) in the sequence Asp-Val-Lys-down arrow-Leu. Although HeV ge notypically resembles members of the Respirovirus and Rubulavirus genera in having potential N-linked glycosylation sites in both the F-1 and F-2 subu nits, we show that phenotypically HeV may more closely resemble members of the Morbillivirus genus that contain N-linked glycans only in the F-2 subun it. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.