Disease relevance of taf

• In this report, we demonstrate that ORF-1 of SFV-3 encodes a transcriptional transactivator designated taf (transactivator of foamy virus) which augments gene expression directed by the viral long terminal repeat (LTR) [1].
• Simian foamy virus type 1 (SFV-1), a member of the Spumavirinae subfamily of retroviruses, encodes a transcriptional transactivator (taf) that strongly augments gene expression directed by the viral long terminal repeat (LTR) (A. Mergia, K. E. S. Shaw, E. Pratt-Lowe, P. A. Barry, and P. A. Luciw, J. Virol. 65:2903-2909, 1991) [2].
• In addition to proviruses containing the complete transactivator gene taf, proviral genomes carrying a specific 295-bp deletion in the taf gene were detected in all monkeys [3].

High impact information on taf

• One of these open reading frames is a viral transactivator, encoded by genes designated taf for SFV and bel-1 for HFV, which augments transcription directed by the long terminal repeat (LTR) through cis-acting targets in the U3 domain of the LTR [4].
• No significant nucleotide sequence homology between these two regions is noted; thus, the SFV-1 taf gene acts through at least two distinct sequence elements in the LTR [2].
• Amino acid homologies between corresponding genes of SFVcpz and HFV range between 86% for the taf gene and 95% for the pol gene [5].
• These target sequences for taf confer responsiveness to a heterologous promoter independent of orientation; thus, they function like conditional enhancers [1].
• The taf responsive elements have been mapped to the U3 region of the LTR, between positions -637 and -180 (+1 represents the transcription initiation site) [1].

Biological context of taf

• Two regions between -637 and -180 in the LTR are targets for taf transactivation [1].

References