The Effect of Monensin on Virion Production and Protein Secretion in Pseudorabies Virus-infected Cells

The effects of monensin on cells infected with pseudorabies virus have been studied. Treatment with monensin (1 microM) prevented the secretion of the 89K pseudorabies virus-induced sulphated glycoprotein. A polypeptide with a mol. wt. of 78K was secreted into the medium from monensin-treated BSC-1 cells. Mannose labelling showed that initial glycosylation proceeded normally in the presence of monensin, although the absence of fucose label revealed that the later stages in processing were blocked. No intracellular accumulation of virus-induced proteins was found in monensin-treated cells. Infectivity assays, measurement of thymidine-labelled particles and electron microscopy showed that monensin blocked the release of virus particles from cells, although viral morphogenesis was unaffected.