Cytoplasm from Poliovirus-infected HeLa Cells inhibits Cell-free Haemoglobin Synthesis

Abstract

INFECTION of HeLa cells with poliovirus causes an inhibition of host cell protein synthesis with a concomitant conversion of polysomes to single ribosomes^{1, 2}. This process is thought to be mediated by a product of the viral genome, for infection of cells with virus particles which have been inactivated by ultraviolet irradiation does not affect the rate of protein synthesis¹. The inhibition acts directly on translation rather than on the production of mRNA^{1, 3}, yet neither chain elongation nor the release of polypeptide chains from ribosomes seems to be affected². Chain initiation, therefore, is the only possible target. Willems and Penman have suggested that cellular mRNA is inactivated after infection, preventing its reassociation with ribosomes³. To test these hypotheses, we assayed for the presence of inhibitors of initiation in poliovirus-infected HeLa cell cytoplasm, using a lysate of rabbit reticulocytes that initiates the synthesis of new polypeptide chains at a rate comparable with that in intact cells.