ABSTRACT Human cytomegalovirus (HCMV), like all herpesviruses, has two phases of its infectious cycle that enable lifelong infection in its host. Lytic infection occurs in differentiated cells and produces infectious virions. Latent infection occurs in undifferentiated cells and is characterized by limited viral gene expression, lack of virion production, and the potential for reactivation. HCMV virions have a tegument layer around the capsid containing proteins important for initial events in infection. In differentiated cells, tegument-delivered viral transactivator pp71 traffics to the nucleus, degrades the cellular repressor DAXX, activates lytic immediate early (IE) genes, and lytic infection is initiated. In undifferentiated cells, tegument-delivered pp71 does not reach the nucleus, DAXX is not degraded, IE transcription is silenced, and latent infection is established. This is because in undifferentiated cells, pp71 and some other tegument proteins remain colocalized with endosomes, while the genome-containing capsid and capsid-associated tegument proteins reach the nucleus. However, the mechanism leading to tegument disassembly and the nuclear localization of tegument-delivered pp71 in differentiated cells and why it does not occur in undifferentiated cells is unknown. Because HCMV enters fibroblasts (where tegument-delivered pp71 reaches the nucleus) by virion fusion at the plasma membrane, but enters myeloid cells (where tegument-delivered pp71 remains cytoplasmic) by endocytosis, I hypothesize that entry by fusion drives pp71 nuclear localization. Here I will test this hypothesis by chemically and biologically inducing HCMV to fuse into myeloid cells and then monitor tegument-delivered pp71 subcellular localization, IE transcription, and infection outcome.