Kaposi's Sarcoma-Associated Herpesvirus ORF57 Protein Enhances mRNA Accumulation Independently of Effects on Nuclear RNA Export
Open Access
- 15 September 2007
- journal article
- research article
- Published by American Society for Microbiology in Journal of Virology
- Vol. 81 (18), 9990-9998
- https://doi.org/10.1128/jvi.00896-07
Abstract
The ORF57 protein expressed by Kaposi's sarcoma-associated herpesvirus (KSHV) during lytic replication is essential for KSHV virion production. ORF57 enhances gene expression by increasing accumulation of target gene mRNAs. ORF57 interacts with the cellular export factor REF and with RNA, suggesting that it may provide target mRNAs with access to REF, which mediates nuclear RNA export by binding to TAP/NXF1. A mutational analysis of ORF57 was performed to study the role of REF binding, RNA interaction, and multimerization in ORF57 function. ORF57 was shown to directly bind RNA. The ability to bind REF did not correlate with ORF57 function in enhancing mRNA accumulation. ORF57 enhanced the nuclear levels of mRNA and PAN, a nuclear KSHV RNA, and the activity of various ORF57 mutants on the levels of mRNA paralleled their ability to enhance nuclear PAN accumulation, suggesting that ORF57 may also act on messenger RNAs by export-independent effects on RNA stability. Finally, an ORF57 mutant lacking a region homologous to a nucleolar localization signal in herpesvirus saimiri was constructed. This mutant retained function, demonstrating that, unlike the ORF57 homolog in herpesvirus saimiri, nucleolar trafficking is not required for ORF57 function in enhancing mRNA accumulation.Keywords
This publication has 37 references indexed in Scilit:
- Human mRNA Export Machinery Recruited to the 5′ End of mRNACell, 2006
- Nucleolar trafficking is essential for nuclear export of intronless herpesvirus mRNAProceedings of the National Academy of Sciences, 2006
- Kaposi's Sarcoma-Associated Herpesvirus Lytic Gene ORF57 Is Essential for Infectious Virion ProductionJournal of Virology, 2006
- Viral Regulation of mRNA ExportJournal of Virology, 2004
- G-quartet-dependent recognition between the FMRP RGG box and RNARNA, 2003
- Epstein-Barr Virus mRNA Export Factor EB2 Is Essential for Production of Infectious VirusJournal of Virology, 2002
- HnRNP L binds a cis-acting RNA sequence element that enables intron-dependent gene expression.Genes & Development, 1995
- A herpesvirus regulatory protein appears to act post-transcriptionally by affecting mRNA processing.Genes & Development, 1992
- Identification and characterization of a yeast nucleolar protein that is similar to a rat liver nucleolar protein.The Journal of cell biology, 1988
- Structural and functional role of leucine residues in proteinsJournal of Molecular Biology, 1973