Cytomegalovirus immediate early 1 protein (IE1) (IE1)

Cytomegalovirus immediate early 1 protein (IE1) is a critical regulatory protein encoded by the UL123 gene of Human Cytomegalovirus (HCMV) [1, 2]. As one of the first proteins synthesized during the lytic cycle or reactivation from latency, IE1 serves as a master regulator that transactivates subsequent viral gene expression [1, 7]. It functions primarily by remodeling the host cellular environment, which includes disrupting PML-associated nuclear bodies (ND10) and antagonizing histone deacetylation to promote a transcriptionally active viral chromatin state [1, 11, 12]. Furthermore, IE1 is a potent antagonist of the host innate immune system, specifically inhibiting type I and type II interferon signaling by sequestering STAT proteins [1, 8, 10]. In the context of disease, IE1 is associated with severe HCMV-related complications in transplant recipients and has been implicated in the progression of certain cancers, such as glioblastoma, through its oncomodulatory effects on cell cycle regulators like p53 and Rb [14, 16, 17]. Due to its essential role and early expression, IE1 is a major target for immunotherapy, including adoptive T-cell transfers and multi-antigen vaccines currently in clinical development [7, 13, 17]. Experimental therapeutic approaches also focus on small molecules designed to disrupt IE1's interactions with host proteins to restore cellular antiviral defenses [8].

Other names

Immediate early protein IE1IE1-7272-kDa immediate-early proteinUL123Regulatory protein IE1

T-cell mediated cytotoxicity through recognition of IE1-derived peptides on MHC molecules, and active immunization to elicit IE1-specific humoral and cellular immune responses [7, 13, 17].