The SWI/SNF Chromatin-remodeling Complex Is a Cofactor for Tat Transactivation of the HIV Promoter
Tat is a critical viral transactivator essential for human immunodeficiency virus (HIV) gene expression. Activation involves binding to an RNA stem-loop structure and recruitment of the positive transcription elongation factor b. Tat also induces the remodeling of a single nucleosome in the HIV promoter. However, the mechanism of this remodeling has remained unclear. Knockdown of INI-1 and BRG-1, two components of the SWI/SNF chromatin-remodeling complex, suppressed Tat-mediated transactivation. Cells lacking INI-1 (G401 and MON) or BRG-1 (C33A) exhibited defective transactivation by Tat that was restored upon INI-1 and BRG-1 expression, respectively. Tat was co-immunoprecipitated with several SWI/SNF subunits, including INI-1, BRG-1, and β-actin. The SWI/SNF complex interacted with the integrated HIV promoter in a Tat-dependent manner. We also found that INI-1 and BRG-1 synergized with the p300 acetyltransferase to activate the HIV promoter. This synergism depended on the acetyltransferase activity of p300 and on Tat Lys50 and Lys51. In conclusion, Tat-mediated activation of the HIV promoter requires the SWI/SNF complex in synergy with the coactivator p300. Tat is a critical viral transactivator essential for human immunodeficiency virus (HIV) gene expression. Activation involves binding to an RNA stem-loop structure and recruitment of the positive transcription elongation factor b. Tat also induces the remodeling of a single nucleosome in the HIV promoter. However, the mechanism of this remodeling has remained unclear. Knockdown of INI-1 and BRG-1, two components of the SWI/SNF chromatin-remodeling complex, suppressed Tat-mediated transactivation. Cells lacking INI-1 (G401 and MON) or BRG-1 (C33A) exhibited defective transactivation by Tat that was restored upon INI-1 and BRG-1 expression, respectively. Tat was co-immunoprecipitated with several SWI/SNF subunits, including INI-1, BRG-1, and β-actin. The SWI/SNF complex interacted with the integrated HIV promoter in a Tat-dependent manner. We also found that INI-1 and BRG-1 synergized with the p300 acetyltransferase to activate the HIV promoter. This synergism depended on the acetyltransferase activity of p300 and on Tat Lys50 and Lys51. In conclusion, Tat-mediated activation of the HIV promoter requires the SWI/SNF complex in synergy with the coactivator p300. Infection by human immunodeficiency virus (HIV) 2The abbreviations used are: HIV, human immunodeficiency virus; nuc, nucleosome; pTEFb, positive transcription elongation factor b; CBP, cAMP-responsive element-binding protein-binding protein; PCAF, p300/CBP-associated factor; LTR, long terminal repeat; CMV, cytomegalovirus; EGFP, enhanced green fluorescent protein; IRES, internal ribosome entry site; GST, glutathione S-transferase; GFP, green fluorescent protein; PMA, phorbol 12-myristate 13-acetate; TSA, trichostatin A; PLB, passive lysis buffer; siRNA, short interfering RNA. sets in motion a complex series of actions that result in the efficient transcription of the viral genome. Once the virus is integrated into the host genome, nucleosomes are deposited at specific positions within the HIV promoter region (1.Verdin E. Paras Jr., P. Van Lint C. EMBO J. 1993; 12: 3249-3259Crossref PubMed Scopus (414) Google Scholar). A large nucleo-some-free region is present between nucleosome (nuc)-0 and nuc-1 and contains binding sites for transcription factors such as NF-κB and Sp1 and other basal transcription factors. Transcription is initiated within this nucleosome-free region. Transcriptional activation of the HIV promoter is associated with the remodeling of nuc-1, which is positioned immediately downstream of the transcription start site (1.Verdin E. Paras Jr., P. Van Lint C. EMBO J. 1993; 12: 3249-3259Crossref PubMed Scopus (414) Google Scholar). In the early phase of HIV infection, cellular transcription factors activate transcription from the HIV promoter. However, the basal HIV promoter shows a striking elongation defect, resulting in the accumulation of short transcripts corresponding to the first ∼50 transcribed nucleotides. This elongation defect is presumed to occur because of deficient loading of the transcription elongation complex pTEFb at the HIV promoter. We propose that the presence of nuc-1 (immediately downstream of the transcription start site) accentuates the elongation defect of the polymerase complex assembled at the HIV promoter. However, the elongation defect of RNA polymerase II assembled at the HIV promoter is not absolute, and basal transcription leads to the accumulation of the viral Tat protein, a potent transactivator. Tat binds to TAR (an RNA stem-loop in the nascent viral RNA) and recruits pTEFb (which contains CDK9 and cyclin T1). The recruitment of pTEFb leads to phosphorylation of the C-terminal domain of RNA polymerase II and increased transcriptional elongation of the HIV promoter. Efficient transcription elongation of the HIV genome in response to Tat leads to more Tat synthesis and generates a Tat-dependent positive feedback loop (2.Karn J. J. Mol. Biol. 1999; 293: 235-254Crossref PubMed Scopus (393) Google Scholar). Tat expression also leads to the remodeling of nuc-1 (1.Verdin E. Paras Jr., P. Van Lint C. EMBO J. 1993; 12: 3249-3259Crossref PubMed Scopus (414) Google Scholar, 3.el Kharroubi A. Martin M.A. Mol. Cell. Biol. 1996; 16: 2958-2966Crossref PubMed Google Scholar). This remodeling is thought to remove an obstacle to RNA polymerase II elongation. Both Tat activities (pTEFb recruitment and nuc-1 remodeling) are thought to synergize in enhancing the ability of RNA polymerase II to elongate. The molecular mechanism of this Tat-induced nucleosome-remodeling event has remained unclear. Chromatin-modifying complexes are classified into two main groups. The first contains factors that mediate covalent modifications of histones. The N-terminal tails of histone proteins are subject to extensive post-transcriptional modifications, including acetylation, phosphorylation, and methylation. The interaction of Tat with a number of histone acetyltransferase complexes such as p300/CBP, p300/CBP-associated factor (PCAF), and human GCN5 and their relevance to Tat-mediated activation of the HIV promoter have been established (4.Marzio G. Tyagi M. Gutierrez M.I. Giacca M. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 13519-13524Crossref PubMed Scopus (266) Google Scholar, 5.Hottiger M.O. Nabel G.J. J. Virol. 1998; 72: 8252-8256Crossref PubMed Google Scholar, 6.Ott M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar, 7.Mujtaba S. He Y. Zeng L. Farooq A. Carlson J.E. Ott M. Verdin E. Zhou M.M. Mol. Cell. 2002; 9: 575-586Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar, 8.Dorr A. Kiermer V. Pedal A. Rackwitz H.R. Henklein P. Schubert U. Zhou M.M. Verdin E. Ott M. EMBO J. 2002; 21: 2715-2723Crossref PubMed Scopus (123) Google Scholar, 9.Benkirane M. Chun R.F. Xiao H. Ogryzko V.V. Howard B.H. Nakatani Y. Jeang K.T. J. Biol. Chem. 1998; 273: 24898-24905Abstract Full Text Full Text PDF PubMed Scopus (253) Google Scholar, 10.Col E. Caron C. Seigneurin-Berny D. Gracia J. Favier A. Khochbin S. J. Biol. Chem. 2001; 276: 28179-28184Abstract Full Text Full Text PDF PubMed Scopus (132) Google Scholar, 11.Kiernan R.E. Vanhulle C. Schiltz L. Adam E. Xiao H. Maudoux F. C. A. Nakatani Y. Jeang K.T. M. Van Lint C. EMBO J. 1999; PubMed Scopus Google Scholar). The complexes the N-terminal tails of of nucleosomes at the HIV of and In Tat is subject to by M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar, 10.Col E. Caron C. Seigneurin-Berny D. Gracia J. Favier A. Khochbin S. J. Biol. Chem. 2001; 276: 28179-28184Abstract Full Text Full Text PDF PubMed Scopus (132) Google Scholar, 11.Kiernan R.E. Vanhulle C. Schiltz L. Adam E. Xiao H. Maudoux F. C. A. Nakatani Y. Jeang K.T. M. Van Lint C. EMBO J. 1999; PubMed Scopus Google Scholar, L. C. P. L. P. H. F. PubMed Scopus Google Scholar). The of complexes proteins that the from to the or of resulting in increased within a of remodeling the SWI/SNF has or the BRG-1, as the W. J. Y. Zhou S. C. M. EMBO J. 1996; PubMed Scopus Google Scholar, 2002; PubMed Scopus Google Scholar, A. C. M. Curr. 2002; 12: PubMed Scopus Google Scholar, W. Y. Zhou S. A. 1996; PubMed Scopus Google Scholar). In to BRG-1 or the complexes subunits, which to to SWI/SNF as as specific to in a 2002; PubMed Scopus Google Scholar, W. Curr. Google Scholar). The remodeling of nuc-1 that at the HIV promoter in response to Tat that Tat an chromatin-remodeling complex to the HIV long terminal to for the of HIV transcription and remodeling is the host factor INI-1 also as or a of the SWI/SNF chromatin-remodeling complex W. J. Y. Zhou S. C. M. EMBO J. 1996; PubMed Scopus Google Scholar). INI-1 binds to HIV and is found in the viral S. W. PubMed Scopus Google Scholar, E. M. S. Ott D. J. Virol. PubMed Scopus Google Scholar). HIV infection, cellular INI-1 from the to the with the HIV complex P. V. E. G. D. Mol. Cell. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). that Tat recruits the SWI/SNF complex to the HIV promoter and is for Tat-mediated activation of the HIV promoter. and HIV M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google the expression for Tat and M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google and INI-1 V. A. PubMed Scopus Google BRG-1 W. Y. A. Cell. 1998; 95: Full Text Full Text PDF PubMed Scopus Google p300 M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google and M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google expression have been the green fluorescent ribosome entry site the of was into the BRG-1 have been P. Proc. Natl. Acad. Sci. U. S. A. 2002; PubMed Scopus Google Scholar). and in with and and and A. D. Verdin E. EMBO J. PubMed Scopus Google Scholar, A. P. Verdin E. EMBO J. 2001; PubMed Scopus Google integrated fluorescent and in with and INI-1 in with and of that an integrated and with viral virus as A. P. Verdin E. EMBO J. 2001; PubMed Scopus Google virus the and the infection, the with to expression in the integrated by and in upon of the expression and integrated used in short RNA the INI-1 gene as M. V. H. D. H. EMBO PubMed Scopus Google Scholar). a was first in with the with and with RNA by the INI-1 gene into M. V. H. D. H. EMBO PubMed Scopus Google Scholar). INI-1 for their ability to INI-1 by and specific used for and and with phorbol 12-myristate for to Cells in A and for on and a and of was with of in at on a with the in loading and co-immunoprecipitated proteins on an and by of the INI-1, BRG-1, and of was with of at and to of for at by extensive with The BRG-1, INI-1, and for with with and by and Tat with pTEFb and with or Tat or in the presence or of p300 expression with and for Cells and in lysis TSA, and and of was with of at on a extensive with PLB, the in loading and on an proteins by with the proteins in and on glutathione on with or Tat in for at on a The with and TSA, and of loading and and Tat proteins by and and INI-1 at a of and the with to the with of and expression and as The was the corresponding for was the activity as an internal The lysis and activities the with a The are from a of and in of was and and to Cells at for at in of and with of short interfering RNA or expression in of lacking and to at in a for and of was to the on a the used to the Cells to between and RNA transcripts of the human and BRG-1 as as a used to the in was into by was used to and and by and by to a of for at was to a of to the by in and for by in a in and and to of at for at and by with for at by of the with of the at used by with and at to for at and with A and and and and complexes in and and for on a at and at for of was with and with and in of by at and to with and RNA of INI-1 and BRG-1 Tat chromatin-remodeling complexes are in the transcriptional activation of the HIV used a a short RNA the INI-1 Cells with the HIV in the presence or of of the short RNA INI-1 by to of INI-1 expression Tat-mediated transactivation of the HIV promoter was basal HIV promoter activity was this used with the in the presence or of expression for Tat and In the of INI-1 on basal HIV promoter activity of INI-1 enhanced the HIV activation by Tat of Tat and INI-1 was by that INI-1 is for Tat activation of the HIV promoter. the of INI-1 and BRG-1 in HIV promoter activity in the This was by of with viral an HIV lacking the In this the HIV promoter expression of A. P. Verdin E. EMBO J. 2001; PubMed Scopus Google Scholar). specific for INI-1 or BRG-1 by resulting in of of the not and to the specific of INI-1 or BRG-1 of INI-1 not the expression of BRG-1, and of BRG-1 not INI-1 Cells with an expression for Tat or the and Tat-mediated transactivation was by expression by of INI-1 or BRG-1 suppressed Tat-mediated transactivation of the HIV promoter as by a in the of also the was for BRG-1, and for INI-1, that of INI-1 and BRG-1 Tat-mediated transcriptional activation of the that the in transactivation was not to activity of the promoter and Tat expression, lacking INI-1 or BRG-1 with a in with or INI-1 and BRG-1 not that Tat activation of the on INI-1 and In the transactivation activity of Tat in the of BRG-1 that INI-1 a in the transactivation as a of the BRG-1 Tat with of the SWI/SNF that Tat requires INI-1 and BRG-1 for transcriptional Tat with SWI/SNF components in used a integrated virus A. D. Verdin E. EMBO J. PubMed Scopus Google Scholar). This of Tat the of the HIV promoter of with We Tat from and for of Tat with components of The that Tat associated with the components of INI-1, BRG-1, and Tat co-immunoprecipitated with BRG-1 not that Tat with the SWI/SNF complex BRG-1 as We used the proteins and as and not with We also the interaction between Tat and SWI/SNF by the INI-1 or BRG-1 complexes specific for of the proteins that BRG-1 co-immunoprecipitated with INI-1 and complexes to with in and by In Tat to the BRG-1 and INI-1 not to or INI-1 with Tat and the Transcriptional that p300 is a in the Tat-dependent activation of the HIV (4.Marzio G. Tyagi M. Gutierrez M.I. Giacca M. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 13519-13524Crossref PubMed Scopus (266) Google Scholar, 5.Hottiger M.O. Nabel G.J. J. Virol. 1998; 72: 8252-8256Crossref PubMed Google Scholar, 6.Ott M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar, 9.Benkirane M. Chun R.F. Xiao H. Ogryzko V.V. Howard B.H. Nakatani Y. Jeang K.T. J. Biol. Chem. 1998; 273: 24898-24905Abstract Full Text Full Text PDF PubMed Scopus (253) Google Scholar). INI-1 and p300 the and with the HIV with or expression for INI-1, and a p300 with a defective histone acetyltransferase domain In the of INI-1, and not basal of Tat activation of transcription in the and of INI-1 or p300 with Tat present at in a in transcription with Tat expression of INI-1, and Tat the HIV to in and to in The activation of the HIV promoter by INI-1, and p300 was was used The on transcription specific for the HIV as the was not with the promoter the HIV activation of the HIV of the HIV genome in the host genome. the of INI-1 on the of the integrated HIV promoter. We viral the and the and an integrated and with the expression for INI-1, and In this the synergy was between INI-1, and Tat This synergy was also on the histone acetyltransferase domain of p300 In conclusion, a striking between the chromatin-remodeling INI-1 and the acetyltransferase p300 transcription of the HIV Tat Lys50 and for the between and p300 transcriptional coactivator Tat at Lys50 M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar, 11.Kiernan R.E. Vanhulle C. Schiltz L. Adam E. Xiao H. Maudoux F. C. A. Nakatani Y. Jeang K.T. M. Van Lint C. EMBO J. 1999; PubMed Scopus Google Scholar, L. C. P. L. P. H. F. PubMed Scopus Google Scholar). This the of Tat from TAR R.E. Vanhulle C. Schiltz L. Adam E. Xiao H. Maudoux F. C. A. Nakatani Y. Jeang K.T. M. Van Lint C. EMBO J. 1999; PubMed Scopus Google Scholar, L. C. P. L. P. H. F. PubMed Scopus Google Scholar, A. C. Kiermer V. Henklein P. Schnölzer M. E. Verdin E. Ott M. Mol. Cell. 12: Full Text Full Text PDF PubMed Scopus Google Scholar). that the synergism between INI-1 and p300 in Tat activation of the on the acetyltransferase activity of the of Tat Lys50 in SWI/SNF recruitment and Lys50 is the of in to leads to the of M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar). of is to the ability of a Tat in which Lys50 and with to the activation by p300 and INI-1 was in and with We also used the to the synergism between BRG-1, and p300 The exhibited activation by Tat that was increased upon BRG-1 expression expression of BRG-1, and Tat the to This synergism was in the presence of the p300 as as the the that the interaction between SWI/SNF and Tat is Tat the interaction of Tat with SWI/SNF is by acetylation, Tat or the was in with or p300. of with an of histone S. Pedal A. A. C. Henklein P. H. M. Verdin E. Ott M. Biol. PubMed Scopus Google and trichostatin an of and II histone We found that Tat with BRG-1 increased in the presence of p300 as by of BRG-1 with Tat The increased Tat We also the of Tat on interaction with of the pTEFb A in the interaction of Tat with cyclin and CDK9 was the not increased for BRG-1 in response to p300. In with the of the for pTEFb was not in response to p300 of Tat Lys50 and to Tat not with the of other Tat sites L. D. C. L. H. P. F. 2001; PubMed Scopus Google Scholar). A in the SWI/SNF complex to with Tat is BRG-1 contains a C-terminal a for Tat has been to with transcriptional PCAF, S. He Y. Zeng L. Farooq A. Carlson J.E. Ott M. Verdin E. Zhou M.M. Mol. Cell. 2002; 9: 575-586Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar). to of the BRG-1 the with the including for Tat binding S. He Y. Zeng L. Farooq A. Carlson J.E. Ott M. Verdin E. Zhou M.M. Mol. Cell. 2002; 9: 575-586Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar). this used proteins to of the BRG-1 P. Proc. Natl. Acad. Sci. U. S. A. 2002; PubMed Scopus Google Scholar). The BRG-1 is within the C-terminal domain of BRG-1 proteins on glutathione and for binding to Tat at Lys50 or to Tat A. C. Kiermer V. Henklein P. Schnölzer M. E. Verdin E. Ott M. Mol. Cell. 12: Full Text Full Text PDF PubMed Scopus Google Scholar). The BRG-1 Tat This binding was on Tat at as Tat not to the interaction was also between BRG-1 and are with the that Tat recruits the SWI/SNF complex to the HIV Tat the of the SWI/SNF to the HIV in that Tat the recruitment of SWI/SNF to the HIV promoter in We the a integrated virus A. D. Verdin E. EMBO J. PubMed Scopus Google with of the in expression in of the Tat was to in response to at and at was from at and and to with specific for BRG-1, and of the with specific for the HIV promoter that BRG-1 and from the LTR, to the HIV promoter in response to In and in with G. Mol. Cell. Biol. 2002; PubMed Scopus Google the transcriptional was to the HIV promoter basal and was in response to that the SWI/SNF complex is to the in response to However, in this not the that recruitment of SWI/SNF to the other in response to that SWI/SNF recruitment Tat and in a Tat-dependent used an integrated virus that Tat A. D. Verdin E. EMBO J. PubMed Scopus Google in and We the with an expression for Tat or the and that of the Tat Tat was was from of the Tat expression and to with specific for BRG-1 and of the with specific for the HIV promoter that BRG-1 was to the HIV was in response to Tat expression that the SWI/SNF complex is to the by Tat in We have that the SWI/SNF chromatin-remodeling complex is a for Tat activation of the HIV promoter. Knockdown of INI-1 and BRG-1, two critical components of chromatin-remodeling Tat-mediated transactivation. INI-1 or BRG-1 defective transactivation by Tat that by INI-1 or BRG-1 expression. Tat with several SWI/SNF subunits, INI-1, BRG-1, and β-actin. SWI/SNF with the integrated HIV promoter in a Tat-dependent manner. In found that INI-1 and BRG-1 with the p300 acetyltransferase to activate the HIV promoter. This synergism is on the histone acetyltransferase activity of p300 and on Tat Lys50 and Lys51. in several have that that proteins and chromatin-remodeling complexes are in a to specific Cell. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, S. J. D. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar, Mol. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, W. Curr. Biol. 1998; PubMed Scopus Google Scholar, Y. J. M.A. M. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar). The of transcription factors and proteins a transcriptional However, factors not in a at the human SWI/SNF complex is at the promoter the histone and PCAF, the SWI/SNF chromatin-remodeling complex is first and is for the recruitment of the histone acetyltransferase complex at the promoter Cell. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, S. J. D. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar). We that and SWI/SNF activate the HIV promoter. This synergy on the acetyltransferase activity of p300 and on Tat Lys50 and Lys51. We M. Schnölzer M. Garnica J. Fischle W. Emiliani S. Rackwitz H.R. Verdin E. Curr. Biol. 1999; 9: 1489-1492Abstract Full Text Full Text PDF PubMed Scopus (252) Google and R.E. Vanhulle C. Schiltz L. Adam E. Xiao H. Maudoux F. C. A. Nakatani Y. Jeang K.T. M. Van Lint C. EMBO J. 1999; PubMed Scopus Google have that p300 Tat at a that a in Tat transcriptional activity in the HIV promoter. We have that Tat as a molecular that the recruitment of to the HIV promoter S. He Y. Zeng L. Farooq A. Carlson J.E. Ott M. Verdin E. Zhou M.M. Mol. Cell. 2002; 9: 575-586Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar, 8.Dorr A. Kiermer V. Pedal A. Rackwitz H.R. Henklein P. Schubert U. Zhou M.M. Verdin E. Ott M. EMBO J. 2002; 21: 2715-2723Crossref PubMed Scopus (123) Google Scholar, A. C. Kiermer V. Henklein P. Schnölzer M. E. Verdin E. Ott M. Mol. Cell. 12: Full Text Full Text PDF PubMed Scopus Google Scholar, M. A. C. Schnölzer M. Henklein P. P. Zhou M.M. Verdin E. PubMed Google Scholar). in the transcription Tat binds to the RNA TAR and recruits pTEFb, including CDK9 and cyclin to the HIV promoter. Tat to the HIV promoter by to the of the complex between and The are with the that Tat the recruitment of the SWI/SNF complex to the HIV to nuc-1 Tat with histone acetyltransferase S. He Y. Zeng L. Farooq A. Carlson J.E. Ott M. Verdin E. Zhou M.M. Mol. Cell. 2002; 9: 575-586Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar, 8.Dorr A. Kiermer V. Pedal A. Rackwitz H.R. Henklein P. Schubert U. Zhou M.M. Verdin E. Ott M. EMBO J. 2002; 21: 2715-2723Crossref PubMed Scopus (123) Google Scholar, V. H. E. Jeang K.T. Nakatani Y. Emiliani S. M. R.E. EMBO J. 2002; 21: PubMed Scopus Google Scholar). We Tat recruits and SWI/SNF in a or The of two complexes in and in the transcriptional activation of several F. PubMed Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, EMBO J. 1999; PubMed Scopus Google Scholar, P. Y. L. F. EMBO J. 1999; PubMed Scopus Google Scholar, A. M. M. W. EMBO J. 1999; PubMed Scopus Google Scholar). has been that the of GCN5 the SWI/SNF complex in an promoter and is for nucleosome remodeling and transcriptional activation P. G. PubMed Scopus Google Scholar). This in GCN5 and SWI/SNF to a promoter P. G. PubMed Scopus Google Scholar). Tat also with PCAF, is that of the HIV promoter SWI/SNF binding to the HIV promoter by a for in the HIV promoter M. A. A. Giacca M. EMBO J. PubMed Scopus Google Scholar). the first of recruitment of a chromatin-remodeling complex to a promoter an The HIV Tat a transcriptional downstream of the transcription start site interaction with the TAR RNA has to Tat has as an transactivator of a more is that nuc-1, the nucleosome that is by SWI/SNF in a Tat-dependent is immediately downstream of the transcription start that Tat to the recruitment of a chromatin-remodeling complex a for the for Tat to RNA of SWI/SNF to TAR Tat positioned immediately at the site of nuc-1 and the remodeling of nuc-1 by We the that SWI/SNF also with Tat the is to the polymerase J. Proc. Natl. Acad. Sci. U. S. A. 1996; PubMed Scopus Google Scholar). However, such a is with the that a single nucleosome is at the of the HIV promoter and that remodeling of nuc-1 is to a specific of RNA polymerase II (1.Verdin E. Paras Jr., P. Van Lint C. EMBO J. 1993; 12: 3249-3259Crossref PubMed Scopus (414) Google Scholar). of the SWI/SNF complex to the HIV promoter in response to Tat is by of the transcriptional have that is to the HIV promoter at the transcription start site specific interaction with G. Mol. Cell. Biol. 2002; PubMed Scopus Google Scholar, F. Y. U. J. Virol. PubMed Scopus Google Scholar). recruits and is to to histone at the of nuc-1 in the of Tat G. Mol. Cell. Biol. 2002; PubMed Scopus Google Scholar). is not Tat leads to the of nuc-1 remodeling to a in the of the for and from the HIV promoter. Tat mediate the of from the HIV promoter of nuc-1 of the of from the HIV promoter and the resulting of to the of the HIV promoter by a mechanism to the of the HIV promoter that has been in response to Tat expression (4.Marzio G. Tyagi M. Gutierrez M.I. Giacca M. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 13519-13524Crossref PubMed Scopus (266) Google Scholar). The of the SWI/SNF chromatin-remodeling complex as a Tat a mechanism for the that Tat leads to the remodeling of The recruitment of SWI/SNF Tat and RNA a mechanism for the recruitment of a chromatin-remodeling complex to a promoter. of this to an integrated of HIV transcriptional in the of We for with the of this and for and Howard and for We for the BRG-1 expression and