An in vitro protein synthesizing system from mouse L fibroblasts infected with reovirus

Abstract

A cell-free system derived from mouse L fibroblasts infected with reovirus is described, which in response to endogenous viral messenger RNA incorporates amino acids in vitro predominantly into eight polypeptide species which, on the basis of their electrophoretic mobility in SDS polyacrylamide gels, are identical with the eight primary reovirus gene products synthexized in vivo. Six of these polypeptides are structural reovirion components; the remaining two are essential nonstructural polypeptides. Background incorporation is low. Synthesis proceeds for 60–90 min at 37°. The relative amounts of each polypeptide species formed in vitro is very similar to that formed in vivo, indicating that the translational controls which operate within the infected cell also operate in the cell-free system. The cleavage of polypeptide μ1 to polypeptide μ2, which proceeds in vivo, does not occur in vitro; nor are nonessential nonstructural reovirus polypeptides formed by the cell-free system.