Polypeptides Synthesized In Vitro by Poly (A)⁺ and Poly (A)^- mRNAs of Rat Ascites Hepatoma AH 7974 Cells

Abstract

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 twodimensional 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.