Polypeptides synthesized in vitro by poly(A)+ and poly(A)- mRNAs of rat ascites hepatoma AH 7974 cells

Polysomal RNA of rat ascites hepatoma AH 7974 cells was fractionated into poly(A)+ and poly(A)- mRNAs and these RNAs were translated into polypeptides in a protein-synthesizing system derived from wheat germ. The analysis of polypeptides synthesized in vitro by two-dimensional gel electrophoresis revealed that there are three classes of polypeptides. The first group can be synthesized equally by both poly(A)+ and poly(A)- mRNAs; the second and third groups are synthesized predominantly by poly(A)+ and poly(A)- mRNAs, respectively. These results suggest that the three classes of polypeptides can be characterized by the presence or absence of poly(A) tails of the corresponding mRNAs.