Characterization of the tumor-associated 38-kd protein of herpes simplex virus type 2.

ABSTRACT

The BglII N DNA fragment of herpes simplex virus type 2 (HSV 2), which is capable of oncogenically transforming cells in vitro, encodes a 37,800-dalton (38-kd) protein that has been seroepidemiologically associated with uterine cervical carcinoma. Polyclonal monospecific antiserum was produced against electrophoretically purified 38 kd from HSV 2-infected cells and used to identify antigenic and biochemical characteristics of the protein as well as to probe transformed cells for the expression of viral 38 kd. The HSV 2 type specificity of the 38-kd protein, previously shown using anti-HSV 2 serum and monoclonal antibodies, was confirmed using anti-38-kd serum. The 38-kd protein of HSV 2 produced in vivo and in vitro displayed type specificity and showed no evidence of posttranslational processing. The 38-kd protein has a relative isoelectric point of 9.1, is synthesized at a maximum level four hours after infection and appears to be a component of the virion. When 35S-methionine radiolabeled 38 kd was immunoprecipitated by anti-38-kd serum, high-molecular-weight proteins (118-140 kd) were also present. However, if prior to reacting with the anti-38-kd serum the high-molecular-weight proteins were separated from 38 kd with sodium dodecyl sulphate-polyacrylamide gel electrophoresis, the only reaction observed with immunoblot was with 38 kd. Therefore, the observed coprecipitation appears to result from the formation of a complex between the proteins and is not the result of shared antigenic determinants. Cells transformed by inactivated HSV 2 were examined for the expression of the 38-kd protein using immunoenzymatic staining. The viral 38-kd protein was not consistently found, but since the protein is reported to be a component of the viral enzyme complex ribonucleotide reductase, it cannot be excluded from possible HSV 2 transformation.