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This Article Full Text (Papers in Press[PDF]) All Versions of this Article: vir.2008.006817-0v1 90/4/944    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Wen, H.-J. Articles by Wood, C. Search for Related Content PubMed PubMed Citation Articles by Wen, H.-J. Articles by Wood, C. Agricola Articles by Wen, H.-J. Articles by Wood, C.

Identification and Characterization of a New KSHV Replication and Transcription Activator/RTA Responsive Element Involved in RTA-Mediated Transactivation

University of Nebraska-Lincoln

¹ E-mail: cwood{at}unlnotes.unl.edu

KSHV RTA is well established as a key transcriptional activator which regulates KSHV life cycle from latency to lytic replication. It is expressed immediately after infection and activates a number of viral genes to lead to viral replication. The RTA responsive element (RRE) in the RTA target gene promoters is critical for RTA to mediate the transactivation. There are a number of non-conserved RREs identified in various RTA responsive promoters, and AT-rich sequences have been proposed to serve as RTA targets but no consensus RREs have so far been identified. Two non-conserved RTA responsive elements (RRE1 and RRE2) which contain AT-rich sequence have been identified previously in the one of KSHV lytic gene promoters, ORF57, which can be strongly activated by RTA. In this study, based on homology to the consensus sequence of EBV RTA RRE we identified a third RTA responsive element (RRE3) in the ORF57 promoter. This RRE consists of GC-rich sequence which can bind RTA both in vitro and in vivo and plays a role in RTA-mediated transactivation of the ORF57 promoter. The presence of two of the three RREs in close proximity to each other is required for optimal RTA-mediated transactivation of the ORF57 promoter even though the presence of only one RRE is needed for RTA binding. Our results suggest that the ability of RTA to mediate transcriptional activation is distinct from its ability to bind to its target elements.

Received 28 August 2008; accepted 27 November 2008.