We have been studying the molecular biology of a significant human pathogen, hepatitis C virus (HCV). Our long-term goal is to understand, at the molecular level, the precise roles of viral proteins, RNA elements, and host factors in HCV replication and pathogenesis. Studies on this enveloped positive-sense RNA virus have been (and continue to be) challenging because of its poor replication in cell cultures and the lack of a convenient animal model. Despite this, our work, together with that of other labs, has resulted in a reasonably complete picture of HCV genome structure, the biosynthesis of viral structural and nonstructural (NS) proteins, and provided assays for each of the predicted or discovered virus-encoded enzymatic activities. During the course of this work, we made two unexpected discoveries which deserve further study. First, we identified a novel 101-base RNA sequence at the 3' terminus of HCV genome RNA. This element is highly conserved among HCV genotypes suggesting an essential role in viral RNA replication, packaging, or both. We propose to characterize the secondary structure of this RNA element, to identify viral or host components which selectively bind to this structure, and to define the molecular determinants of these RNA- protein interactions. Successful development of infectious clones or other assays for HCV RNA replication and/or encapsidation will allow us to directly test the functional importance of this element. Second, we found that the 58-kDa NS5A protein, a presumed RNA replicase component and one of the two remaining NS proteins without known activities, is posttranslationally phosphorylated on serine residues. NS5A phosphorylation occurs in various cell cultures and cell-free assays and preliminary results suggest that it may be the target of one or more host kinases. We propose to identify the kinase(s) responsible for NS5A phosphorylation and assess the importance of NS5A phosphorylation in HCV replication and virus-host interactions. These studies should provide valuable new information on the HCV 3' terminal element, the NS5A phosphoprotein, and may lead to the identification of host factors required for HCV replication. Such analyses are critical for understanding each step in the virus life cycle at a level which will allow the design of protective vaccines and effective therapy for chronically infected patients.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA057973-07
Application #
2712663
Study Section
Experimental Virology Study Section (EVR)
Program Officer
Cole, John S
Project Start
1992-08-01
Project End
2001-05-31
Budget Start
1998-06-01
Budget End
1999-05-31
Support Year
7
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Washington University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Laidlaw, Stephen M; Marukian, Svetlana; Gilmore, Rachel H et al. (2017) Tumor Necrosis Factor Inhibits Spread of Hepatitis C Virus Among Liver Cells, Independent From Interferons. Gastroenterology 153:566-578.e5
Billerbeck, Eva; Wolfisberg, Raphael; Fahnøe, Ulrik et al. (2017) Mouse models of acute and chronic hepacivirus infection. Science 357:204-208
Moreno, Elena; Gallego, Isabel; Gregori, Josep et al. (2017) Internal Disequilibria and Phenotypic Diversification during Replication of Hepatitis C Virus in a Noncoevolving Cellular Environment. J Virol 91:
Ramanan, Vyas; Trehan, Kartik; Ong, Mei-Lyn et al. (2016) Viral genome imaging of hepatitis C virus to probe heterogeneous viral infection and responses to antiviral therapies. Virology 494:236-47
Gu, Meigang; Rice, Charles M (2016) The Spring ?-Helix Coordinates Multiple Modes of HCV (Hepatitis C Virus) NS3 Helicase Action. J Biol Chem 291:14499-509
Luna, Joseph M; Michailidis, Eleftherios; Rice, Charles M (2016) Mopping up miRNA: An integrated HBV transcript disrupts liver homeostasis by sequestering miR-122. J Hepatol 64:257-259
Scheel, Troels K H; Luna, Joseph M; Liniger, Matthias et al. (2016) A Broad RNA Virus Survey Reveals Both miRNA Dependence and Functional Sequestration. Cell Host Microbe 19:409-23
Swanson, Michael D; Boudreaux, Daniel M; Salmon, Loïc et al. (2015) Engineering a therapeutic lectin by uncoupling mitogenicity from antiviral activity. Cell 163:746-58
Saeed, Mohsan; Andreo, Ursula; Chung, Hyo-Young et al. (2015) SEC14L2 enables pan-genotype HCV replication in cell culture. Nature 524:471-5
Luna, Joseph M; Scheel, Troels K H; Danino, Tal et al. (2015) Hepatitis C virus RNA functionally sequesters miR-122. Cell 160:1099-110

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