The Kaposi's sarcoma-associated herpesvirus ORF57 protein: a pleurotropic regulator of gene expression.
Herpesviridae comprises over 120 viruses infecting a wide range of vertebrates including humans and livestock. Herpesvirus infections typically produce dermal lesions or immune cell destruction, but can also lead to oncogenesis, especially with KSHV (Kaposi's sarcoma-associated herpesvirus). All herpesviruses are nuclear replicating viruses that subvert cellular processes such as nucleocytoplasmic transport for their advantage. For virus replication to take over the cell and produce lytic infection requires that virus gene expression outpace that of the host cell. KSHV ORF57 (open reading frame 57) appears to play a major role in this by (i) serving as a nuclear export receptor to carry intronless viral mRNAs out of the nucleus and (ii) inhibiting expression of intron-containing host mRNAs. As most of the virally encoded mRNAs are intronless compared with host cell mRNAs, these two mechanisms are critical to overcoming host gene expression.
Malik
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The Wellcome Trust Centre for Cell Biology and Institute of Cell Biology, University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK. p.malik@ed.ac.uk
Schirmer
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D002467:Cell Nucleus / Q000502:physiology / Q000821:virology; D003593:Cytoplasm / Q000502:physiology / Q000821:virology; D015967:Gene Expression Regulation, Viral; D006564:Herpesviridae / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D021381:Protein Transport; D012328:RNA Viruses / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D012514:Sarcoma, Kaposi / Q000821:virology*; D015534:Trans-Activators / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics*
C415247:ORF57 protein, Herpesvirus saimiri; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; D014764:Viral Proteins