The genome of cowpox virus contains a gene related to those encoding the epidermal growth factor, transforming growth factor alpha and vaccinia growth factor

Cowpox virus (CPV) is a member of the Orthopoxvirus genus and has the genet ic capacity to encode a multitude of genes that interfere with the host inf lammatory and immune response or modulate the physiological state of infect ed and non-infected cells. Among these CPV factors are receptors homologous to interferon and tumor necrosis factor receptors and also a viral cellula r serine-proteinase analog. Here we describe the detection of a CPV gene th at encodes a protein homologous to epidermal growth factor, transforming gr owth factor alpha and poxvirus growth factors, such as the vaccinia growth factor (VGF). The VGF and other poxvirus growth factors are produced early in the infection and are secreted into the medium where they bind to the EG F receptors, generating mytotic responses. The cowpox growth factor (CGF) g ene was detected in three copies on the virus genome by PCR, and by norther n and southern blot hybridization using VGF nucleotide sequences as primers and probes. The CPV gene has a strong nucleotide and predicted amino acid similarity with VGF, and is also produced early in the infection.