Post-translational regulation of rotavirus protein NSP1 expression in mammalian cells.
The nonstructural rotavirus protein NSP1 binds specifically to viral mRNAs and to interferon regulatory factor 3 (IRF3), inducing IRF3 degradation through a proteasome-dependent pathway. By using a vaccinia virus expression system in mammalian cells, we found that the yield of NSP1 was 8- and 13-fold lower than the viral proteins VP2 or NSP3, respectively; while in the presence of proteasome inhibitors such difference could be reduced to 2- to 2.5-fold, respectively. The susceptibility of NSP1 to proteasome degradation was fully reversed in a dose-dependent manner by transfection with the full complement of 11 molecules of translation-competent rotavirus mRNAs, but this effect was abrogated by the protein synthesis inhibitor cycloheximide. These results demonstrate that NSP1 is degraded through a proteasome-dependent pathway, and viral proteins, alone or in combination with viral mRNAs, interfere with such degradation.
Piña-Vázquez
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C
Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.
De Nova-Ocampo
M
M
Guzmán-León
S
S
Padilla-Noriega
L
L
D000818:Animals; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012401:Rotavirus / Q000235:genetics / Q000378:metabolism*; D014616:Vaccinia virus / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; C104282:nsp1 protein, Rotavirus