Human cytomegalovirus (HCMV), a member of the herpesvirus family, is the leading viral cause of birth defects and causes significant morbidity and mortality in immunosuppressed individuals. This virus appears to affect the host cell metabolism in ways that mimic processes involved in cell activation, but the molecular basis of these effects and their relationship to viral replication have yet to be elucidated. A major goal of our studies has been to decipher the mechanisms by which HCMV usurps various cellular signaling and regulatory pathways to facilitate its replication. Specific focus has been on how the virus activates the cell to a state that is optimal for DNA replication, and at the same time alters the activity of selected cellular proteins so that viral replication proceeds at the expense of the host. Our studies have shown that the HCMV-mediated effects on the cell cycle are at the level of transcription, subcellular localization of proteins, and protein phosphorylation and degradation. In this renewal application, we propose to continue to investigate the mechanisms by which HCMV exploits the host cell. The approach is to couple in vivo genetic and functional analyses with in vitro biochemical and molecular assays to achieve the following specific aims: 1. Determine the effects of the HCMV infection on the localization of and protein-protein interactions between key cell cycle-related proteins; 2. Determine the function of the cyclin-dependent kinases in the replication of HCMV; and 3. Determine the role of the ubiquitination-proteasome pathway in mediating the effects of the infection on the host cell. These studies are important not only to advance our knowledge of how the complex interactions of viral and host functions relate to viral replication and pathogenesis, but also to help elucidate the general mechanisms that operate to control the cell cycle.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Virology Study Section (VR)
Program Officer
Daschner, Phillip J
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California San Diego
Schools of Arts and Sciences
La Jolla
United States
Zip Code
Spector, Deborah H (2015) Human cytomegalovirus riding the cell cycle. Med Microbiol Immunol 204:409-19
Tran, Karen; Mahr, Jeffrey A; Spector, Deborah H (2010) Proteasome subunits relocalize during human cytomegalovirus infection, and proteasome activity is necessary for efficient viral gene transcription. J Virol 84:3079-93
Tran, Karen; Kamil, Jeremy P; Coen, Donald M et al. (2010) Inactivation and disassembly of the anaphase-promoting complex during human cytomegalovirus infection is associated with degradation of the APC5 and APC4 subunits and does not require UL97-mediated phosphorylation of Cdh1. J Virol 84:10832-43
Sanders, Rebecca L; Spector, Deborah H (2010) Human cytomegalovirus IE2 86 and IE2 40 proteins differentially regulate UL84 protein expression posttranscriptionally in the absence of other viral gene products. J Virol 84:5158-70
Kapasi, Anokhi J; Clark, Charles L; Tran, Karen et al. (2009) Recruitment of cdk9 to the immediate-early viral transcriptosomes during human cytomegalovirus infection requires efficient binding to cyclin T1, a threshold level of IE2 86, and active transcription. J Virol 83:5904-17
Tran, Karen; Mahr, Jeffrey A; Choi, Jiwon et al. (2008) Accumulation of substrates of the anaphase-promoting complex (APC) during human cytomegalovirus infection is associated with the phosphorylation of Cdh1 and the dissociation and relocalization of APC subunits. J Virol 82:529-37
Sanders, Rebecca L; Del Rosario, Christia J; White, Elizabeth A et al. (2008) Internal deletions of IE2 86 and loss of the late IE2 60 and IE2 40 proteins encoded by human cytomegalovirus affect the levels of UL84 protein but not the amount of UL84 mRNA or the loading and distribution of the mRNA on polysomes. J Virol 82:11383-97
Kapasi, Anokhi J; Spector, Deborah H (2008) Inhibition of the cyclin-dependent kinases at the beginning of human cytomegalovirus infection specifically alters the levels and localization of the RNA polymerase II carboxyl-terminal domain kinases cdk9 and cdk7 at the viral transcriptosome. J Virol 82:394-407
Sanders, Rebecca L; Clark, Charles L; Morello, Christopher S et al. (2008) Development of cell lines that provide tightly controlled temporal translation of the human cytomegalovirus IE2 proteins for complementation and functional analyses of growth-impaired and nonviable IE2 mutant viruses. J Virol 82:7059-77
Sanchez, Veronica; Mahr, Jeffrey A; Orazio, Nicole I et al. (2007) Nuclear export of the human cytomegalovirus tegument protein pp65 requires cyclin-dependent kinase activity and the Crm1 exporter. J Virol 81:11730-6

Showing the most recent 10 out of 25 publications