ZHANGFEI, also known as ZF, is a basic region-leucine zipper transcriptional factor that has been implicated in herpes virus infection cycle and related cellular processes. ZHANGFEI protein has a negatively charged active N-terminus, a leucine zipper of six heptad leucine repeats separated by a conserved six amino acid spacer, a basic domain and a bZIP region. ZHANGFEI strongly activates transcription and suppresses the expression of HSV proteins in cells infected with the virus in a HCFC1 dependent manner. It also suppresses the HCFC1 dependent transcriptional activation by CREB3 and reduces the amount of CREB3 in the cell.