H
IPR036963

Tat domain superfamily

InterPro entry
Short nameTat_dom_sf
Overlapping entries
 

Description

Like other lentiviruses, Human immunodeficiency virus 1 (HIV-1) encodes a trans-activating regulatory protein (Tat), which is essential for efficient transcription of the viral genome
[5, 3]
. Tat acts by binding to an RNA stem-loop structure, the trans-activating response element (TAR), found at the 5' ends of nascent HIV-1 transcripts. In binding to TAR, Tat alters the properties of the transcription complex, recruits a positive transcription elongation complex (P-TEFb) and hence increases the production of full-length viral RNA
[3]
. Tat protein also associates with RNA polymerase II complexes during early transcription elongation after the promoter clearance and before the synthesis of full-length TAR RNA transcript. This interaction of Tat with RNA polymerase II elongation complexes is P-TEFb-independent. There are two Tat binding sites on each transcription elongation complex; one is located on TAR RNA and the other one on RNA polymerase II near the exit site for nascent mRNA transcripts which suggests that two Tat molecules are involved in performing various functions during a single round of HIV-1 mRNA synthesis
[4]
.

The minimum Tat sequence that can mediate specific TAR bindingin vitrohas been mapped to a basic domain of 10 amino acids, comprising mostly Arg and Lys residues. Regulatory activity, however, also requires the 47 N-terminal residues, which interact with components of the transcription complex and function as a transcriptional activation domain
[3, 1, 2]
.

References

1.Trans-activation by HIV-1 Tat via a heterologous RNA binding protein. Selby MJ, Peterlin BM. Cell 62, 769-76, (1990). View articlePMID: 2117500

2.Direct interaction of human TFIID with the HIV-1 transactivator tat. Kashanchi F, Piras G, Radonovich MF, Duvall JF, Fattaey A, Chiang CM, Roeder RG, Brady JN. Nature 367, 295-9, (1994). View articlePMID: 8121496

3.NMR structure of a biologically active peptide containing the RNA-binding domain of human immunodeficiency virus type 1 Tat. Mujeeb A, Bishop K, Peterlin BM, Turck C, Parslow TG, James TL. Proc. Natl. Acad. Sci. U.S.A. 91, 8248-52, (1994). View articlePMID: 8058789

4.A bimolecular mechanism of HIV-1 Tat protein interaction with RNA polymerase II transcription elongation complexes. Zhou C, Rana TM. J. Mol. Biol. 320, 925-42, (2002). View articlePMID: 12126615

5.The biochemistry of AIDS. Vaishnav YN, Wong-Staal F. Annu. Rev. Biochem. 60, 577-630, (1991). View articlePMID: 1883204

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