%0 Journal Article %A Sandford, Gordon R. %A Schumacher, Uwe %A Ettinger, Jakob %A Brune, Wolfram %A Hayward, Gary S. %A Burns, William H. %A Voigt, Sebastian %T Deletion of the rat cytomegalovirus immediate-early 1 gene results in a virus capable of establishing latency, but with lower levels of acute virus replication and latency that compromise reactivation efficiency %D 2010 %J Journal of General Virology, %V 91 %N 3 %P 616-621 %@ 1465-2099 %R https://doi.org/10.1099/vir.0.016022-0 %I Microbiology Society, %X The immediate-early 1 (IE1) and IE2 proteins encoded by the major immediate-early (MIE) transcription unit of cytomegaloviruses are thought to play key roles in the switch between latent- and lytic-cycle infection. Whilst IE2 is essential for triggering the lytic cycle, the exact roles of IE1 have not been resolved. An MIE–exon 4-deleted rat cytomegalovirus (ΔIE1) failed to synthesize the IE1 protein and did not disperse promyelocytic leukaemia bodies early post-infection, but was still capable of normal replication in fibroblast cell culture. However, ΔIE1 had a diminished ability to infect salivary glands persistently in vivo and to reactivate from spleen explant cultures ex vivo. Quantification of viral genomes in spleens of infected animals revealed a reduced amount of ΔIE1 virus produced during acute infection, suggesting a role for IE1 as a regulator in establishing a chronic or persistent infection, rather than in influencing the latency or reactivation processes more directly. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.016022-0