A technique has been devised which allows us to label predominantly echovirus-12-specific
proteins: upon
infection in the presence of D-(--)-2-(alpha-hydroxybenzyl)benzimidazole plus
actinomycin D the shut-off of host-cell
protein synthesis takes place as in infected, untreated cells, but the bulk of
viral protein synthesis is inhibited. Upon removal of
2-(alpha-hydroxybenzyl)benzimidazole a peak of
viral protein synthesis is visible 3 h later. The time course of appearance of
viral proteins is followed by
dodecyl sulfate/
polyacrylamide gel electrophoresis of the
proteins which had been pulse-labeled at different times post-
infection. The
protein patterns induced in the infected cells by echovirus 12 and poliovirus 2 are compared; though they are different, some analogies are observed. The molecular weights of the
polypeptides are determined. In the presence of
amino acid analogs cleavage of
viral proteins is impaired. A group of large
proteins up to Mr 220,000 is detectable in the infected cell which ordinarily is not observed. The 220,000-Mr
protein may represent the translation product of the total
viral RNA. The hierarchy of the virus-specific
proteins originating from post-translational cleavage is discussed.