Characterization of the African swine fever virus protein p49: a new late structural polypeptide

The open reading frame B438L, located within the Eco RI B fragment of the African swine fever virus genome, is predicted to encode a protein of 438 amino acids with a molecular mass of 49·3 kDa. It presents a cell attachment RGD (Arg–Gly–Asp) motif but no other significant similarity to protein sequences in databases. Northern blot and primer extension analysis showed that B438L is transcribed only at late times during virus infection. The B438L gene product has been expressed in Escherichia coli , purified and used as an antigen for antibody production. The rabbit antiserum specific for pB438L recognized a protein of about 49 kDa in virus-infected cell extracts. This protein was synthesized late in infection by all the virus strains tested, was located in cytoplasmic virus factories and appeared as a structural component of purified virus particles.