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Updated: May 15, 2026
In situ Subcellular Fractionation of Adherent and Non-adherent Mammalian Cells
Published on: July 23, 2010
Changes in subcellular localization reveal interactions between human cytomegalovirus terminase subunits
Jian Ben Wang1, Yali Zhu, Michael A McVoy
1Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298-0163, USA.
Background:
During herpesvirus replication, terminase packages viral DNA into capsids. The subunits of herpes simplex virus terminase, UL15, UL28, and UL33, assemble in the cytoplasm prior to nuclear import of the complex.
Methods:
To detect similar interactions between human cytomegalovirus terminase subunits, the orthologous proteins UL89, UL56, and UL51 were expressed in HEK-293 T cells (via transfection) or insect cells (via baculovirus infection) and subcellular localizations were detected by cellular fractionation and confocal microscopy.
Results:
In both cell types, UL56 and UL89 expressed alone were exclusively cytoplasmic, whereas UL51 was ~50% nuclear. Both UL89 and UL56 became ~50% nuclear when expressed together, as did UL56 when expressed with UL51. Nuclear localization of each protein was greatest when all three proteins were co-expressed.
Conclusions:
These results support inclusion of UL51 as an HCMV terminase subunit and suggest that nuclear import of human cytomegalovirus terminase may involve nuclear import signals that form cooperatively upon subunit associations.
