Subcellular distribution of the major immediate early proteins of human cytomegalovirus changes during infection

Abstract

The 72K immediate early (IE) 1 protein of human cytomegalovirus and the 68K protein, also encoded by the IEI gene, were detected by immunoelectron microscopy using monoclonal antibodies specific for the 68K or 72K proteins. Early after infection, both proteins were localized to the nucleus, but with different localization patterns. Late after infection, both of the proteins decreased markedly in the nucleus, in which nucleocapsids appeared. Simultaneously, the 68K protein became diffusely distributed in the cytoplasm and the plasma membrane, whereas the 72K protein was distributed in the nuclear envelope and the plasma membrane. Both proteins were also observed in the coating membrane of the extracellular dense bodies.

A comparative study of congenital and postnatally acquired human cytomegalovirus infection in infants: lack of expression of viral immediate early protein in congenital cases

“…Our observations are consistent with a previous study using immunoelectron microscopy which demonstrated the subcellular distribution of IE1 products during infection in vitro. IE antigens were localized in the nuclei during the early phase and in the cytoplasm during the late phase (Tsutsui and Yamazaki 1991). Moreover, the transcripts of IE gene were also detected in the nuclei of IE proteinpositive cells with nuclear and cytoplasmic type of staining.…”

A Guide to Viral Inclusions, Membrane Rearrangements, Factories, and Viroplasm Produced During Virus Replication

“…Dense bodies exit the cell to become extracellular dense bodies (Craighead et al, 1972). Interestingly, HHV-5 immediate early IE1 proteins also become associated with extracellular dense bodies despite no reported localization to their intracellular relations (Tsutsui and Yamazaki, 1991). Purified extracellular dense bodies are mostly composed of UL83 but have a full complement of viral glycoproteins (Irmiere and Gibson, 1983).…”

Infection of APC by Human Cytomegalovirus Controlled Through Recognition of Endogenous Nuclear Immediate Early Protein 1 by Specific CD4+ T Lymphocytes

“…In agreement with other reports (38,39), staining for IE1 was exclusively nuclear in our confocal microscopy experiments. However, the extra-nuclear presence of IE1, although minor, has been reported in other studies (56,57). The visualization of IE1 on membranes outside the nucleus using cell membrane fractionation (56) and electron microscopy (57) suggests that IE1 may be present in cell organelles.…”

“…However, the extra-nuclear presence of IE1, although minor, has been reported in other studies (56,57). The visualization of IE1 on membranes outside the nucleus using cell membrane fractionation (56) and electron microscopy (57) suggests that IE1 may be present in cell organelles. This localization needs to be examined by electron microscopy in our cell model, and it will be of interest to visualize colocalization with specific markers of Ag processing that may provide the functional basis for IE1 presentation by MHC-II.…”