The major immediate-early (IE) gene of human cytomegalovirus (CMV) is believed to have a decisive role in acute infection and its activity is an important indicator of viral reactivation from latency.Although a variety of gene products are expressed from this region, the 72-kDa IE1 and the Outdoors Tools 86-kDa IE2 nuclear phosphoproteins are the most abundant and important.Both proteins have long been FLAX recognized as promiscuous transcriptional regulators.More recently, a critical role of the IE1 and IE2 proteins in counteracting nonadaptive host cell defense mechanisms has been revealed.
In this review we will briefly summarize the available literature on IE1- and IE2-dependent mechanisms contributing to CMV evasion from intrinsic and innate immune responses.