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Hepatitis A virus (HAV) proteinase 3C inhibits HAV IRES‐dependent translation and cleaves the polypyrimidine tract‐binding protein
Author(s) -
Kanda T.,
GaussMüller V.,
Cordes S.,
Tamura R.,
Okitsu K.,
Shuang W.,
Nakamoto S.,
Fujiwara K.,
Imazeki F.,
Yokosuka O.
Publication year - 2010
Publication title -
journal of viral hepatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 100
eISSN - 1365-2893
pISSN - 1352-0504
DOI - 10.1111/j.1365-2893.2009.01221.x
Subject(s) - internal ribosome entry site , polypyrimidine tract binding protein , virology , translation (biology) , hepatitis a virus , polypyrimidine tract , biology , microbiology and biotechnology , chemistry , virus , messenger rna , rna binding protein , biochemistry , gene
Summary. Hepatitis A virus (HAV) infection is still an important issue worldwide. A distinct set of viruses encode proteins that enhance viral cap‐independent translation initiation driven by an internal ribosome entry site (IRES) and suppress cap‐dependent host translation. Unlike cytolytic picornaviruses, replication of HAV does not cause host cell shut off, and it has been questioned whether HAV proteins interfere with its own and/or host translation. HAV proteins were coexpressed in Huh‐7 cells with reporter genes whose translation was initiated by either cap‐dependent or cap‐independent mechanisms. Among the proteins tested, HAV proteinase 3C suppressed viral IRES‐dependent translation. Furthermore, 3C cleaved the polypyrimidine tract‐binding protein (PTB) whose interaction with the HAV IRES had been demonstrated previously. The combined results suggest that 3C‐mediated cleavage of PTB might be involved in down‐regulation of viral translation to give way to subsequent viral genome replication.