Defect in poliovirus maturation under hypotonic conditions

Abstract

Reduction of osmotic pressure in the medium in which poliovirus-infected cells are incubated results in inhibition of the formation of infectious virions and virus-specific particles sedimenting with the rate of mature virions. Under hypotonic conditions, however, synthesis of “soluble” virus-specific proteins and 74 S particles (procapsids) is observed. The 74 S particles formed under hypotonic and isotonic conditions do not differ from each other by sedimentation in sucrose density gradients, by buoyant density in CsCl, or by the spectrum of polypeptides detected by electrophoresis in polyacrylamide gel. No significant differences have been found in the set of polypeptides in the fraction of “soluble” proteins in extracts of productively or abortively infected cells. Taking into consideration earlier evidence that infectious poliovirus RNA is formed under hypotonic conditions (Tolskaya et al., 1966), a conclusion is drawn that under these conditions maturation of virions from the available precursors is disturbed.