Oncolytic ElB-55K-mutant adenoviruses have entered phase III clinical trials. However, the basis for their selective replication in tumor cells is poorly understood. Work of this lab has shown that ElB-55K-mutant viruses selectively replicate in and kill S phase cells better than G1 cells; this is likely to account for the selective replication in tumors. This research seeks to understand the tumor-selective nature of the E1B- 55K-mutant by understanding its S phase-selective and G1-restricted nature. Results from the previous period showed that late viral gene expression is suppressed in G1 cells at the level of translation, apparently in response to the E4orf1 or E4orf2 genes. The polysomal distribution of late viral mRNA in S phase and G1 cells infected with ElB-55K-mutant viruses suggests that late viral translation is restricted in G1 cells at the level of ribosome shunting. The E1B-55K protein of the wild-type virus promotes viral translation in association with the E4orl""""""""6 protein and host cell factors. A candidate host cell factor has been mapped to the RUNX1 gene.
Three specific aims are proposed in this application.
Aim 1 seeks to determine how late viral translation is suppressed in G1-infected cells by comparing viral mRNA synthesis/ed in G1- and S phase-infected cells and by measuring the rates of key translational steps in synchronized and infected cells. This will test the hypothesis that ribosome shunting is decreased in the G1-infected cell.
Aim 2 will elucidate the role of E4orfl and E4orf2 in attenuating late viral translation and restricting virus growth in G1. Viruses defective in either E4orlT or E4orf2 and the E1B-55K genes will be prepared and evaluated with respect to the cell cycle-restriction. Translation directed by ribosome scanning and ribosome shunting will he compared in cells infected with cell cycle-restricted and non-restricted mutant viruses to test the hypothesis that E4orf 1 attenuates translation at the level of ribosome shunting and that this is the basis for the G1-restriction.
Aim 3 will identify the RUNX1 isoform important for E1B-55K function and determine if its activity during an infection is cell cycle-dependent. Candidate isoforms will be over expressed to determine if they compensate for the loss of E1B-55K function and RNA interference will be used to ablate RUNX1 expression to determine the importance of RUNX1 to adenovirus infection. ? ? ?

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-IDM-G (02))
Program Officer
Daschner, Phillip J
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Wake Forest University Health Sciences
Schools of Medicine
United States
Zip Code
Nichols, Gena J; Schaack, Jerome; Ornelles, David A (2009) Widespread phosphorylation of histone H2AX by species C adenovirus infection requires viral DNA replication. J Virol 83:5987-98
Spurgeon, Megan E; Ornelles, David A (2009) The adenovirus E1B 55-kilodalton and E4 open reading frame 6 proteins limit phosphorylation of eIF2alpha during the late phase of infection. J Virol 83:9970-82
Thomas, Michael A; Broughton, Robin S; Goodrum, Felicia D et al. (2009) E4orf1 limits the oncolytic potential of the E1B-55K deletion mutant adenovirus. J Virol 83:2406-16
Garnett, C T; Talekar, G; Mahr, J A et al. (2009) Latent species C adenoviruses in human tonsil tissues. J Virol 83:2417-28
Marshall, Leslie J; Moore, Amy C; Ohki, Misao et al. (2008) RUNX1 permits E4orf6-directed nuclear localization of the adenovirus E1B-55K protein and associates with centers of viral DNA and RNA synthesis. J Virol 82:6395-408
Ornelles, David A; Broughton-Shepard, Robin N; Goodrum, Felicia D (2007) Analysis of adenovirus infections in synchronized cells. Methods Mol Med 131:83-101
Gustafsson, B; Huang, W; Bogdanovic, G et al. (2007) Adenovirus DNA is detected at increased frequency in Guthrie cards from children who develop acute lymphoblastic leukaemia. Br J Cancer 97:992-4
Hart, Lori S; Ornelles, David; Koumenis, Constantinos (2007) The adenoviral E4orf6 protein induces atypical apoptosis in response to DNA damage. J Biol Chem 282:6061-7
Weitzman, Matthew D; Ornelles, David A (2005) Inactivating intracellular antiviral responses during adenovirus infection. Oncogene 24:7686-96
Hart, Lori S; Yannone, Steven M; Naczki, Christine et al. (2005) The adenovirus E4orf6 protein inhibits DNA double strand break repair and radiosensitizes human tumor cells in an E1B-55K-independent manner. J Biol Chem 280:1474-81

Showing the most recent 10 out of 19 publications