An Internal Ribosome Entry Site Directs Translation of the Murine Gammaherpesvirus 68 MK3 Open Reading Frame
AUTOR(ES)
Coleman, Heather M.
FONTE
American Society for Microbiology
RESUMO
The gammaherpesviruses characteristically drive the proliferation of latently infected lymphocytes. The murine gammaherpesvirus 68 (MHV-68) MK3 protein contributes to this process in vivo by evading CD8+-T-cell recognition during latency, as well as during lytic infection. We analyzed some of the molecular mechanisms that control MK3 expression. No dedicated MK3 mRNA was detected. Instead, the MK3 open reading frame (ORF) was transcribed as part of a bicistronic mRNA, downstream of a previously unidentified ORF, 13M. The 13M/MK3 promoter appeared to extend approximately 1 kb 5′ of the transcription start site and included elements both dependent on and independent of the ORF50 lytic transactivator. MK3 was translated from the bicistronic transcript by virtue of an internal ribosome entry site (IRES) element. RNA structure mapping identified two stem-loops between 13M and MK3 that were sufficient for IRES activity in a bicistronic reporter plasmid and a third stem-loop just within the MK3 coding sequence, with a subtler, perhaps regulatory role. Overall, translation of the MHV-68 MK3 bore a striking resemblance to that of the Kaposi's sarcoma-associated herpesvirus vFLIP, suggesting that IRES elements are a common theme of latent gammaherpesvirus immune evasion in proliferating cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=296059Documentos Relacionados
- Kaposi's Sarcoma-Associated Herpesvirus vCyclin Open Reading Frame Contains an Internal Ribosome Entry Site
- Murine Gammaherpesvirus 68 Open Reading Frame 31 Is Required for Viral Replication
- Murine Gammaherpesvirus 68 Open Reading Frame 11 Encodes a Nonessential Virion Component
- Disruption of the Murine Gammaherpesvirus 68 M1 Open Reading Frame Leads to Enhanced Reactivation from Latency
- Mechanism of the Internal Ribosome Entry Site-mediated Translation of Serine Hydroxymethyltransferase 1*