Role of picornavirus 2A protease in inhibition of host nucleo-cytoplasmic transport


Park, Nogi.. (2009). Role of picornavirus 2A protease in inhibition of host nucleo-cytoplasmic transport. Theses and Dissertations Collection, University of Idaho Library Digital Collections.

Role of picornavirus 2A protease in inhibition of host nucleo-cytoplasmic transport
Park, Nogi.
Picornaviruses--Genetics Cytogenetics
Microbiology, Molecular Biology, and Biochemistry
Rhinovirus and poliovirus contain positive stranded RNA as their genome and perform viral translation and replication in the host cytoplasm. Previous studies showed that certain host nuclear factors interact with the viral genome and proteins in the cytoplasm. Consistent with cytoplasmic accumulations of host nuclear factors, the inhibition of certain host nuclear import pathways during infection was demonstrated along with the cleavage of nuclear pore complex (NPC) proteins such as Nup153, Nup98 and Nup62. These Nups contain phenylalanine-glycine (FG) rich regions that play an important role in nuclear transport.;The cleavage mechanism of Nups and the contribution of Nup cleavage in the inhibition of nuclear import during infection have not been explained clearly. I hypothesized that viral proteases specifically targeted Nups to inhibit nuclear import during infection. To test this hypothesis, this project has pursued the following questions; (1) Are viral proteases responsible for the Nup cleavage? (2) Where are the cleavage sites in target Nups? (3) What is the consequence of Nup cleavage on NPC composition during viral infection?;To test the contribution of viral protease in Nup cleavage, uninfected HeLa whole cell lysates and purified Nup62 and Nup98 were incubated with purified viral proteases, 2Apro and 3Cpro . These assays show that 2A pro plays a major role in the cleavage of Nup62 and Nup98.2Apro cleavage sites in Nup62 and Nup98 were identified by a combination of amino-terminal sequencing of cleavage products and sequence analysis and confirmed by in vitro cleavage assay with in vitro translated mutant Nups. Identified cleavage sites in both Nup62 and Nup98 were located in between the N-terminal FG rich region and C-terminal region. Immunofluorescence assays with mock- and virus-infected HeLa cells shows that the N-terminal FG rich regions of Nup62 and Nup98 were released from the NPC during infection.;Based on these results, this study suggests that poliovirus and rhinovirus 2Apro specifically targets the FG regions of Nups to inhibit normal host nuclear transport.
Thesis (Ph. D., Microbiology, Molecular Biology and Biochemistry)--University of Idaho, August 2009.
Major Professor:
Kurt E. Gustin.
Defense Date:
August 2009.
Format Original:
x, 174 leaves :ill. (some col.) ;29 cm.

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