A cellular response protein induced during HSV-1 infection inhibits viral replication by interacting with ATF5

Studies of herpes simplex virus type 1(HSV-1)infection have shown that many known and unknown cellular molecules involved in viral proliferation are up-regulated following HSV-1 infection.In this study,using two-dimensional polyacrylamide gel electrophoresis,we found that the expression of the HSV-1 infection response repressive protein(HIRRP,GI 16552881)was up-regulated in human L02 cells infected with HSV-1.HIRRP,an unknown protein,was initially localized in the cytoplasm and then translocated into the nucleus of HSV-1-infected cells.Further analysis showed that HIRRP represses HSV-1proliferation by inhibiting transcription of the viral genome by interacting with the cellular transcription factor,ATF5,via its N-terminal domain.ATF5 represses the transcription of many host genes but can also act as an activator of genes containing a specific motif.We found that ATF5 promotes the proliferation of HSV-1 via a potential mechanism by which ATF5 enhances the transcription of viral genes during the course of an HSV-1 infection;HIRRP then induces feedback repression of this transcription by interacting with ATF5.