Variola, the causative agent of smallpox, is a highly infectious double-stranded DNA virus of
the orthopox genus that replicates within the cytoplasm of infected cells. For unknown
reasons prominent skin manifestations, including" pox," mark the course of this systemic
human disease. Here we characterized smallpox growth factor (SPGF), a protein containing
an epidermal growth factor (EGF)-like domain that is conserved among orthopox viral
genomes, and investigated its possible mechanistic link. We show that after recombinant …