Derivation and functional characterization of a consensus DNA binding sequence for the tas transcriptional activator of simian foamy virus type 1.

Published

Journal Article

Although DNA binding sites specific for the Bel-1 and Tas transcriptional activators, encoded, respectively, by the human and simian foamy viruses, have been mutationally defined, they show little evident sequence identity. As a result, the sequence determinants for DNA binding by both Bel-1 and Tas have remained unclear. Here, we report the use of a novel in vivo randomization and selection strategy to identify a Tas DNA binding site consensus. This approach takes advantage of the fact that Tas can effectively activate gene expression in yeast cells via a Tas DNA binding site derived from the simian foamy virus type 1 (SFV-1) internal promoter. The defined Tas DNA binding site consensus extends over approximately 25 bp and contains a critical core sequence of approximately 5 bp. Positions adjacent to this core sequence, while clearly also subject to selection, show a significantly higher level of sequence variation. Surprisingly, the wild-type SFV-1 internal promoter Tas DNA binding site fails to conform to the consensus at several positions. Further analysis demonstrated that the consensus sequence bound Tas more effectively than did the wild-type sequence in vitro and could mediate an enhanced Tas response in vivo when substituted into the SFV-1 internal promoter context. These findings explain the limited sequence identity observed for mutationally defined Tas or Bel-1 response elements and should facilitate the identification of Tas DNA target sites located elsewhere in the SFV-1 genome.

Full Text

Duke Authors

Cited Authors

  • Kang, Y; Cullen, BR

Published Date

  • July 1998

Published In

Volume / Issue

  • 72 / 7

Start / End Page

  • 5502 - 5509

PubMed ID

  • 9621006

Pubmed Central ID

  • 9621006

International Standard Serial Number (ISSN)

  • 0022-538X

Language

  • eng

Conference Location

  • United States