Efficient trans-activation by the HIV-2 Tat protein requires a duplicated TAR RNA structure.
AUTOR(ES)
Berkhout, B
RESUMO
Human immunodeficiency viruses HIV-1 and HIV-2 encode a Tat protein that activates transcription from the long terminal repeats. The target for transactivation is termed the trans-acting responsive (TAR) element. TAR has an extensively folded RNA secondary structure and is present at the 5' end of all viral mRNAs. Considerable similarities exist between both Tat and TAR of the two viruses. The TAR element of HIV-2 (TAR-2) resembles a tandem duplication of the TAR-1 hairpin structure. Tat-2 conserves many of the protein domains in Tat-1, although it is slightly larger than its counterpart. Given the similarity between the two Tat proteins, it is somewhat unexpected that HIV-2 Tat (Tat-2) only poorly activates the heterologous TAR-1 element. Here, we tested whether the duplicated structure of TAR-2 is required for full Tat-2 activity. We show that the addition of a second TAR hairpin to TAR-1 increased its Tat-2 responsiveness by 3-fold.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=330604Documentos Relacionados
- The basic RNA-binding domain of HIV-2 Tat contributes to preferential trans-activation of a TAR2-containing LTR.
- Bioassay for trans-activation using purified human immunodeficiency virus tat-encoded protein: trans-activation requires mRNA synthesis.
- Trans-activation of HIV-1 LTR-directed gene expression by tat requires protein kinase C.
- Trans-activation of HIV-1 LTR-directed gene expression by tat requires protein kinase C
- Exon2 of HIV-2 Tat contributes to transactivation of the HIV-2 LTR by increasing binding affinity to HIV-2 TAR RNA.