Viruses provide powerful tools to study fundamental cellular mechanisms. Using human adenovirus as a model we have identified the cellular DNA repair machinery as an obstacle to viral replication. Cellular DNA repair pathways produce concatemers of the double-stranded viral genome during infection with viruses deleted of the E4 region. The Mre11/Rad50/NBS1 complex is essential for concatemer formation. This cellular complex is important for double-strand DNA break repair, meiotic recombination and telomere maintenance. Defects in Mre11 and NBS1 genes predispose to malignancy in AT-like disorder (ATLD) and Nijmegen breakage syndrome respectively. We show that adenovirus possesses two mechanisms to inactivate this cellular complex. One viral protein (E4orf3) causes mislocalization of the Mre11 complex and two other viral proteins (E4orf6/E1b55K) induce degradation of Mre11 and Rad50 proteins. These viral proteins prevent concatemerization and also cause cell transformation using a """"""""hit-and-run"""""""" strategy. We propose to investigate the role of the Mre11 complex in concatemer formation and the mechanism used by the virus to target this complex for degradation. We will use biochemical and molecular approaches to determine the activities of the Mre11 complex required for concatemerization of viral genomes. We will examine interactions of the Mre11 complex with the viral proteins and determine whether the E1b55K/E4orf6 complex can ubiquitinate the Mre11 protein to cause its degradation. We have observed that infection with viruses lacking the E4orf6/E1b55K complex results in activation of DNA repair signaling pathways. We will study these events and determine how they are blocked by E4orf6/E1b55K. We will also look at the consequences for the cell of Mre11 degradation and its effect on DNA repair. These studies will provide insights into cellular pathways that sense and respond to DNA damage and will also shed light on how viral oncoproteins cause transformation.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA097093-03
Application #
6891065
Study Section
Experimental Virology Study Section (EVR)
Program Officer
Daschner, Phillip J
Project Start
2003-04-01
Project End
2008-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
3
Fiscal Year
2005
Total Cost
$320,804
Indirect Cost
Name
Salk Institute for Biological Studies
Department
Type
DUNS #
078731668
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Pancholi, Neha J; Weitzman, Matthew D (2018) Serotype-specific restriction of wild-type adenoviruses by the cellular Mre11-Rad50-Nbs1 complex. Virology 518:221-231
Dybas, Joseph M; Herrmann, Christin; Weitzman, Matthew D (2018) Ubiquitination at the interface of tumor viruses and DNA damage responses. Curr Opin Virol 32:40-47
Pancholi, Neha J; Price, Alexander M; Weitzman, Matthew D (2017) Take your PIKK: tumour viruses and DNA damage response pathways. Philos Trans R Soc Lond B Biol Sci 372:
Reyes, Emigdio D; Kulej, Katarzyna; Pancholi, Neha J et al. (2017) Identifying Host Factors Associated with DNA Replicated During Virus Infection. Mol Cell Proteomics 16:2079-2097
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Herrmann, Christin; Avgousti, Daphne C; Weitzman, Matthew D (2017) Differential Salt Fractionation of Nuclei to Analyze Chromatin-associated Proteins from Cultured Mammalian Cells. Bio Protoc 7:
Avgousti, Daphne C; Herrmann, Christin; Kulej, Katarzyna et al. (2016) A core viral protein binds host nucleosomes to sequester immune danger signals. Nature 535:173-7
Kulej, Katarzyna; Avgousti, Daphne C; Weitzman, Matthew D et al. (2015) Characterization of histone post-translational modifications during virus infection using mass spectrometry-based proteomics. Methods 90:8-20
Weitzman, Matthew D; Weitzman, Jonathan B (2014) What's the damage? The impact of pathogens on pathways that maintain host genome integrity. Cell Host Microbe 15:283-94
Chaurushiya, Mira S; Lilley, Caroline E; Aslanian, Aaron et al. (2012) Viral E3 ubiquitin ligase-mediated degradation of a cellular E3: viral mimicry of a cellular phosphorylation mark targets the RNF8 FHA domain. Mol Cell 46:79-90

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