Visna virus encodes a post-transcriptional regulator of viral structural gene expression.

Journal Article

Visna virus is an ungulate lentivirus that is distantly related to the primate lentiviruses, including human immunodeficiency virus type 1 (HIV-1). Replication of HIV-1 and of other complex primate retroviruses, including human T-cell leukemia virus type I (HTLV-I), requires the expression in trans of a virally encoded post-transcriptional activator of viral structural gene expression termed Rev (HIV-1) or Rex (HTLV-I). We demonstrate that the previously defined L open reading frame of visna virus encodes a protein, here termed Rev-V, that is required for the cytoplasmic expression of the incompletely spliced RNA that encodes the viral envelope protein. Transactivation by Rev-V was shown to require a cis-acting target sequence that coincides with a predicted RNA secondary structure located within the visna virus env gene. However, Rev-V was unable to function by using the structurally similar RNA target sequences previously defined for Rev or Rex and, therefore, displays a distinct sequence specificity. Remarkably, substitution of this visna virus target sequence in place of the HIV-1 Rev response element permitted the Rev-V protein to efficiently rescue the expression of HIV-1 structural proteins, including Gag, from a Rev- proviral clone. These results suggest that the post-transcriptional regulation of viral structural gene expression may be a characteristic feature of complex retroviruses.

Full Text

Duke Authors

Cited Authors

  • Tiley, LS; Brown, PH; Le, SY; Maizel, JV; Clements, JE; Cullen, BR

Published Date

  • October 1990

Published In

Volume / Issue

  • 87 / 19

Start / End Page

  • 7497 - 7501

PubMed ID

  • 2170981

International Standard Serial Number (ISSN)

  • 0027-8424

Language

  • eng

Conference Location

  • United States