Abstract: Disclosed is a recombinant polypeptide for facilitating membrane fusion. The recombinant polypeptide having a sequence with at least 80% sequence identity with the ectodomain of p14 fusion-associated small transmembrane (FAST) protein and having a functional myristoylation motif, a transmembrane domain from a FAST protein and a sequence with at least 80% sequence identity with the endodomain of p15 FAST protein. A targeting ligand can be added to the recombinant polypeptide for selective fusion. The recombinant polypeptide can be included in the membrane of a liposome, or the like, to facilitate the delivery of bioactive compounds, such as siRNA, or the recombinant polypeptide can be mixed with a lipid carrier and added to cultured cells to induce cell-cell fusion and heterokaryon formation.

Abstract: In accordance with the present invention, a family of membrane fusion protein and polynucleotides encoding the proteins have been identified. The proteins and nucleotides are derived from the family Reoviridae. Two membrane fusion proteins have been isolated from reoviruses isolated from poikilothermic hosts: the p14 protein from reptilian reovirus (RRV) isolated from python, and the p16 protein from aquareovirus (AQV) isolated from salmon. The genes encoding these proteins have been cloned and sequenced. Analysis of the amino acid sequences of these proteins show that both lack the typical fusion peptide motif found in other membrane fusion proteins. Expression of these proteins in cells results in cell-cell fusion.