Section 12
Chapter 11,513

The human herpesvirus-8 ORF 57 gene and its properties

Bello, L.J.; Davison, A.J.; Glenn, M.A.; Whitehouse, A.; Rethmeier, N.; Schulz, T.F.; Barklie Clements, J.

Journal of General Virology 80: 3207-3215


ISSN/ISBN: 0022-1317
PMID: 10567653
Accession: 011512934

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Human herpesvirus-8 (HHV-8) is a gamma(2) lymphotropic herpesvirus associated with Kaposi's sarcoma, a major neoplasm of AIDS patients, and with other AIDS-related neoplasms. The HHV-8 ORF 57 gene is conserved throughout the herpesvirus family and has a herpes simplex virus type 1 homologue, IE63 (also termed ICP27), which is an essential regulatory protein and acts at both transcriptional and post-transcriptional levels. We show that, contrary to the published HHV-8 sequence, which predicts a protein of 275 amino acids, the ORF 57 gene is spliced, contains a single intron and encodes a protein of 455 amino acids. For several gammaherpesviruses examined, the upstream coding exon is 16-17 amino acids in length and is rich in methionine residues. When ORF 57 was fused to the gene for enhanced green fluorescent protein (EGFP), the fusion protein exhibited a punctate nuclear distribution that co-localized with the cellular splicing factor SC-35. Unlike the IE63-EGFP fusion protein, ORF 57-EGFP did not shuttle from the nucleus to the cytoplasm in the presence of actinomycin D. However, ORF 57-EGFP was capable of shuttling from a transfected monkey nucleus to a recipient mouse nucleus in an interspecies heterokaryon assay. These data indicate that HHV-8 ORF 57 and IE63 possess certain common properties.

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