Functional organization of the Bel-1 trans activator of human foamy virus.

Journal Article (Journal Article)

Human foamy virus encodes a 300-amino-acid nuclear regulatory protein termed Bel-1 that is required for human foamy virus replication in culture. Bel-1 is a potent trans-activator of gene expression directed by the homologous HFV long terminal repeat as well as the long terminal repeat of human immunodeficiency virus type 1. We have used mutational analysis to define several discrete functional domains within Bel-1. The C-terminal approximately 50 amino acids of Bel-1 are shown to be essential for Bel-1 activity but can be effectively substituted by the C-terminal activation domain of VP16. We therefore conclude that the Bel-1 C terminus forms part of an activation domain. Mutations within a central, approximately 100-amino-acid segment of Bel-1 preclude trans-activation by either Bel-1 or the Bel-1/VP16 chimera. These sequences are therefore proposed to direct the interaction of Bel-1 with its viral DNA target sequences. A short Bel-1 segment located between the activation and binding domains is shown to mediate the nuclear localization of this regulatory protein. Although the functional organization of Bel-1 therefore appears comparable to that reported for other eukaryotic transcriptional activators, Bel-1 does not contain sequences homologous to known transcriptional activation or DNA-binding motifs.

Full Text

Duke Authors

Cited Authors

  • He, F; Sun, JD; Garrett, ED; Cullen, BR

Published Date

  • April 1993

Published In

Volume / Issue

  • 67 / 4

Start / End Page

  • 1896 - 1904

PubMed ID

  • 8383217

Pubmed Central ID

  • PMC240257

International Standard Serial Number (ISSN)

  • 0022-538X

Digital Object Identifier (DOI)

  • 10.1128/JVI.67.4.1896-1904.1993


  • eng

Conference Location

  • United States