Construction of a green fluorescent protein (GFP) Avian Metapneumovirus (AMPV) recombinant lacking the small hydrophobic (SH) protein gene shows that giant syncytial formations are not a result of the reduction in genome size

An AMPV reverse-genetics system was used to create a virus lacking the entire SH open reading frame which produced unusual giant syncytial formation in cell culture. The replacement of the gene with GFP resulted in virus which also produced the same syncytial formation. The intrinsic fluorescent properties of the virus may prove useful in pathogenesis studies. The similarity of size of the 2 genes suggests that the altered cytopathic effect did not result from the shortening of the genome and possible consequential effects on the transcription or translation of the following attachment and polymerase protein genes