Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gene 50 is the only immediate-early gene that appears to be conserved among the characterized gammaherpesviruses. It has recently been demonstrated for the human viruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) that ectopic expression of the gene 50-encoded product in some latently infected cell lines can lead to the induction of virus replication, indicating that gene 50 is likely to play a pivotal role in regulating gammaherpesvirus reactivation. Here we demonstrate that the murine gammaherpesvirus 68 (gammaHV68) gene 50 is an immediate-early gene and that transcription of gammaHV68 gene 50 leads to the production of both spliced and unspliced forms of the gene 50 transcript. Splicing of the transcript near the 5' end serves to extend the gene 50 open reading frame, as has been observed for the gene 50 transcripts encoded by KSHV and herpesvirus saimiri (Whitehouse et al., J. Virol. 71:2550-2554, 1997; Lukac et al., Virology 252:304-312, 1998; Sun et al., Proc. Natl. Acad. Sci. USA 95:10866-10871, 1998). Reverse transcription-PCR analyses, coupled with S1 nuclease protection assays, provided evidence that gene 50 transcripts initiate at several sites within the region from bp 66468 to 66502 in the gammaHV68 genome. Functional characterization of the region upstream of the putative gene 50 transcription initiation site demonstrated orientation-dependent promoter activity and identified a 110-bp region (bp 66442 to 66552) encoding the putative gene 50 promoter. Finally, we demonstrate that the gammaHV68 gene 50 can transactivate the gammaHV68 gene 57 promoter, a known early gene target of the gene 50-encoded transactivator in other gammaherpesviruses. These studies show that the gammaHV68 gene 50 shares several important molecular similarities with the gene 50 homologs in other gammaherpesviruses and thus provides an impetus for future studies analyzing the role of the gammaHV68 gene 50-encoded protein in acute virus replication and reactivation from latency in vivo.
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PMID:Characterization of gammaherpesvirus 68 gene 50 transcription. 1064 77

Kaposi's sarcoma-associated herpesvirus (KSHV) latently infects KS tumors, primary effusion lymphomas (PELs), and PEL cell lines. K12 (T0.7) is the most abundant transcript expressed in latent KSHV infection. We characterize here the K12 transcript from a PEL tumor prior to passage in cell culture. The PEL tumor KSHV K12 transcript contained additional complex nucleotide repeat elements compared to the previously described K12 message of the BCBL-1 PEL cell line. The PEL tumor lacked kaposin B, the predominant BCBL-1 K12 protein product, but encoded kaposins A and C. The K12 transcript was spliced and the splicing event occurred in all KSHV isolates tested. The 5' end of the K12 transcript was mapped by 5' RACE (rapid amplification of cDNA ends) and S1 nuclease protection assays and was at the site of an active promoter. This work demonstrates that the K12 transcript contains variable, complex repeat elements, is spliced and is expressed from a novel KSHV promoter.
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PMID:The Kaposi's sarcoma-associated herpesvirus K12 transcript from a primary effusion lymphoma contains complex repeat elements, is spliced, and initiates from a novel promoter. 1241 30