Lytic infection of pseudorabies virus in the presence of spermine, spermidine, or DFMO

The effects of polyamines (spermine or spermidine) and DFMO (an ornithine decarboxylase inhibitor) on the infection of LM (tk−) cells by pseudorabies virus (PRV) were investigated. Results from radioactive methionine labeling showed that the synthesis of viral proteins was not affected; however, the expression of a distinctive cellular protein ( 27 kDa) was induced after the treatment of spermine or spermidine. Using plaque assay, we found that the plaque formation of PRV was not affected by these three reagents either. Furthermore, the effects of these drugs on the transcription of PRV immediate-early gene (IE) promoter were examined by CAT assay, and results showed weak stimulation of transcription by these drugs. Taken together, our results demonstrated that lytic infection of PRV was not influenced by addition of exogenous polyamines or depletion of endogenous polyamines; this conclusion was similar to earlier studies by using herpes simplex virus.