MAPPING AND SEQUENCE OF THE GENE ENCODING THE AFRICAN SWINE FEVER VIRION PROTEIN OF M(R) 11500

The gene encoding the African swine fever virus protein of M(r) 11 500, present in the virus particle, has been mapped and sequenced in the genome of the Vero cell-adapted virus strain BA71V. A serum raised against virion proteins of M(r) 12 000 to 13 000 isolated from polyacrylamide gels was used to screen a plasmid expression library, containing viral DNA random fragments, that expresses viral polypeptides fused to beta-galactosidase. Using this method, we have identified and sequenced the open reading frame (ORF) Al37R, which initiates at the right end of the EcoRI A restriction fragment and extends into the EcoRI F fragment. Expression of the protein in Escherichia coli has confirmed that ORF A137R encodes a protein with an M(r) of about 12000. A specific serum was raised against the E. coli-expressed protein, and has been used to identify the protein encoded by the ORF, which is translated at late times of infection and incorporated into the virus particle. Immunofluorescence experiments have shown that the protein localizes in virus factories.