Cell type dependence of herpes simplex virus gene expression and of processing of viral protein

R325, a recombinant virus constructed from the wild type herpes simplex virus 1 strain F [HSV-1(F)] carries a 500 bp deletion in the alpha 22 gene. Both viruses are temperature sensitive for growth and late gene expression in HEp-2 cells. To determine the properties of alpha 22 protein and to identify the product of the non deleted 5' portion of the alpha 22 gene in R325, infected BHK and HEp-2 cells incubated at permissive and non-permissive temperatures were electrophoretically separated in denaturing polyacrylamide gels, electrically transferred to a nitrocellulose sheet and reacted with rabbit polyclonal antibody to an oligopeptide synthesized according to the predicted aminoacid sequence of the 5' terminus of alpha 22. The results were as follows: the authentic alpha 22 protein was detected in infected BHK and HEp-2 cells maintained at either 34 degrees C (permissive) or 39 degrees C (non-permissive) temperatures, the truncated protein specified by R325 accumulated at 39 degrees C but not at 34 degrees C. Furthermore, the proteins made in BHK cells were processed to higher apparent molecular weights and formed several bands in contrast to the single band formed by the protein made in HEp-2 cells; the temporal pattern of expression of HSV-1(F) and R325 at the 39 degrees C was more advanced in BHK cells than in HEp-2 cells. Specifically, in BHK cells at the non-permissive temperature alpha protein synthesis was shut off earlier and gamma proteins not made in infected HEp-2 cells were detected. These studies suggest that folding of viral proteins may be in part cell dependent and either compensate or exacerbate the effects of mutations in specific genes.