African swine fever virus-induced polypeptides in Vero cells

African swine fever virus induces in Vero cells 81 acid and 14 basic polypeptides which account for most of the information content of the virus DNA. The kinetics and the cytosine arabinoside sensitivity of the synthesis of the virus-induced polypeptides showed the existence of three classes of proteins, two early and one late. Most of the early proteins were synthesized along the whole replication cycle, but the synthesis of some of the early proteins was switched-off after virus DNA replication. Late proteins were defined as those whose synthesis did not take place in the presence of cytosine arabinoside. Cell iodination with chloramine T showed the presence in the membrane of the infected cells of two major virus-induced proteins of relative molecular weights 220K and 32K. Protein p220 was incorporated into the membrane very soon after its synthesis, before the appearance of intracellular infectious virus, whereas in the case of protein p32 there was a delay between synthesis and incorporation into the membrane.