Cytomegalovirus Immediate-Early 2 protein (IE2)

Cytomegalovirus antigen IE2 refers to the Immediate-Early 2 (IE2) protein encoded by the major immediate-early gene region of human cytomegalovirus (HCMV). This protein is a nuclear phosphoprotein, typically with a molecular weight of approximately 86 kDa, and is one of the most abundantly expressed immediate-early proteins during HCMV infection. It is a principal transcriptional activator for HCMV early genes, and also functions as a negative autoregulator. IE2 also contributes to evasion from host defense mechanisms by interfering with interferon responses, and inducing proteasomal degradation of CD83.

IE2 acts as the principal transcriptional activator for HCMV early genes, playing an essential role in initiating viral replication and lytic infection. It also functions as a negative autoregulator by repressing its own promoter activity and that of other immediate-early genes through binding to specific DNA sequences near transcription start sites.