Macromolecular synthesis at the early stage of herpes simplex virus type 2 (HSV-2) latency in a human neuroblastoma cell line IMR-32: repression of late viral polypeptide synthesis and accumulation of cellular heat-shock proteins

Abstract

We have shown that a latent infection of herpes simplex virus type 2 (HSV-2) can be established in a human neuroblastoma cell line IMR-32 if the infected cells are cultured at 40°C. In the present study, viral polypeptides and cellular heat-shock proteins which were synthesized in HSV-2 infected IMR-32 cells cultured at 40°C were analyzed by polyacrylamide gel electrophoresis. It was found that the synthesis of late viral polypeptide ICP 5 was markedly reduced in the infected cells at 40°C as compared with those at 37°C. Although infection of IMR-32 cells with HSV-2 at 40°C resulted in shutoff of cellular protein synthesis, it was found that some cellular heat-shock proteins (90, 72 and 70 kd polypeptides) were synthesized and accumulated intracellularly. These findings suggest that modification of cascade regulation of HSV-2 polypeptide synthesis and/or accumulation of heat-shock proteins may be involved in the incomplete arrest of virus growth and in survival of the infected cells, leading to the establishment of HSV-2 latency in IMR-32 cells.