MACROMOLECULAR-SYNTHESIS IN CELLS INFECTED BY FROG VIRUS-3 .10. INHIBITION OF CELLULAR PROTEIN-SYNTHESIS BY HEAT-INACTIVATED VIRUS

Heat-inactivated frog virus 3 (ΔFV3) inhibits host cell protein synthesis without interfering with protein synthesis directed by active FV3. An examination of various parameters of cellular protein synthesis after exposure of cells to ΔFV3 revealed the following. (i) The rate of inhibition was multiplicity dependent. (ii) There was a rapid disaggregation of both free and membrane-bound polysomes. (iii) Rates of protein chain elongation remained unaltered. (iv) There was neither a detectable breakdown nor modification of cellular mRNAs; the mRNAs isolated from ΔFV3-treated cells could be translated in vitro and the pattern of the translational products appeared identical to that of mRNAs from untreated cells. These data are consistent with the conclusion that inhibition of host cell protein synthesis by ΔFV3 is the result of a selective effect on a step(s) essential for the initiation of translation of cellular mRNAs. © 1979.