Experiments in this proposal seek to define how sigma3, one of the most abundant reovirus proteins in the virion and in the infected cell, interacts with viral protein mu1 to regulate viral entry and protein synthesis.
In Aim I, molecular and biochemical approaches will be used to define the pH-sensitive and protease- dependent structural changes in capsid protein sigma3 that are required for reovirus particles to enter cells. Since little is known about how nonenveloped viruses breach cell membranes, these studies should elucidate fundamental cell entry mechanisms used by an important group of infectious agents. The results of these studies will contribute to an understanding of molecular mechanisms of viral persistence, since sigma3 mutations which influence virion disassembly are selected during the establishment of persistent reovirus infections. Experiments in Aim II address the fundamental question of how viral translation comes to predominate over cellular translation in reovirus- infected cells and how viral protein sigma3 affects this switch. Sigma3 belongs to a class of viral modulators which influence protein synthesis by binding dsRNA and preventing the activation of the dsRNA-dependent interferon-induced eIF2alpha kinase, PKR. However recent data indicate that sigma3 molecules from strains with distinct translational phenotypes are virtually identical in proposed dsRNA-binding sites. This suggests that in reovirus- infected cells, sigma3 activity is regulated. Several possible forms of regulation will be investigated. Biochemical and molecular approaches are proposed to test the hypothesize that sigma3 molecules differ in their affinity for mu1, and that mu1 influences the translational balance in infected cells by determining the level of sigma3 that is capable of binding dsRNA. Other molecular and genetic experiments explore an intriguing correlation between the ability of reovirus to shut off cellular translation and the cellular localization pattern of sigma3 molecules. These studies address the hypothesis that viral translation predominates in reovirus-infected cells because of a localized dsRNA-binding activity of sigma3. Results from studies in Aim II will contribute to an understanding of how viruses modulate the cellular translation machinery to favor their own replication.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI045990-02
Application #
6170610
Study Section
Experimental Virology Study Section (EVR)
Program Officer
Meegan, James M
Project Start
1999-08-01
Project End
2004-07-31
Budget Start
2000-08-01
Budget End
2001-07-31
Support Year
2
Fiscal Year
2000
Total Cost
$213,243
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Nygaard, Rachel M; Lahti, Linse; Boehme, Karl W et al. (2013) Genetic determinants of reovirus pathogenesis in a murine model of respiratory infection. J Virol 87:9279-89
Schulz, Wade L; Haj, Amelia K; Schiff, Leslie A (2012) Reovirus uses multiple endocytic pathways for cell entry. J Virol 86:12665-75
Nygaard, Rachel M; Golden, Joseph W; Schiff, Leslie A (2012) Impact of host proteases on reovirus infection in the respiratory tract. J Virol 86:1238-43
Alain, Tommy; Kim, Tom Sy; Lun, Xueqing et al. (2007) Proteolytic disassembly is a critical determinant for reovirus oncolysis. Mol Ther 15:1512-21
Goodman, Alan G; Smith, Jennifer A; Balachandran, Siddharth et al. (2007) The cellular protein P58IPK regulates influenza virus mRNA translation and replication through a PKR-mediated mechanism. J Virol 81:2221-30
Smith, Jennifer A; Schmechel, Stephen C; Raghavan, Arvind et al. (2006) Reovirus induces and benefits from an integrated cellular stress response. J Virol 80:2019-33
Smith, Jennifer A; Schmechel, Stephen C; Williams, Bryan R G et al. (2005) Involvement of the interferon-regulated antiviral proteins PKR and RNase L in reovirus-induced shutoff of cellular translation. J Virol 79:2240-50
Nibert, Max L; Odegard, Amy L; Agosto, Melina A et al. (2005) Putative autocleavage of reovirus mu1 protein in concert with outer-capsid disassembly and activation for membrane permeabilization. J Mol Biol 345:461-74
Golden, Joseph W; Bahe, Jessica A; Lucas, William T et al. (2004) Cathepsin S supports acid-independent infection by some reoviruses. J Biol Chem 279:8547-57
Golden, Joseph W; Linke, Jessica; Schmechel, Stephen et al. (2002) Addition of exogenous protease facilitates reovirus infection in many restrictive cells. J Virol 76:7430-43

Showing the most recent 10 out of 11 publications