title: HIV-1 Tat stimulates transcription complex assembly through recruitment of TBP in the absence of TAFs.
abstract: The human immunodeficiency virus type I (HIV-1) transactivator protein Tat is an unusual transcriptional activator that is thought to act solely by promoting RNA polymerase II processivity. Here we study the mechanism of Tat action by analyzing transcription complex (TC) assembly in vivo using chromatin immunoprecipitation assays. We find, unexpectedly, that like typical activators Tat dramatically stimulates TC assembly. Surprisingly, however, the TC formed on the HIV-1 long terminal repeat is atypical and contains TATA-box-binding protein (TBP) but not TBP-associated factors (TAFs). Tat function involves direct interaction with the cellular cofactor positive transcription elongation factor b (P-TEFb). Artificial tethering of P-TEFb subunits to HIV-1 promoter DNA or nascent RNA indicates that P-TEFb is responsible for directing assembly of a TC containing TBP but not TAFs. On the basis of this finding, we identify P-TEFb-dependent cellular promoters that also recruit TBP in the absence of TAFs. Thus, in mammalian cells transcription of protein-coding genes involves alternative TCs that differ by the presence or absence of TAFs.
authors.affiliation: Howard Hughes Medical Institute, Program in Gene Function, University of Massachusetts Medical School, Worcester, USA.
authors.forename: Tamal
authors.initials: T
authors.lastname: Raha
authors.forename: S W Grace
authors.initials: SW
authors.lastname: Cheng
authors.forename: Michael R
authors.initials: MR
authors.lastname: Green
mesh_terms: D000818:Animals; D015696:Gene Products, tat / Q000378:metabolism*; D005914:Globins / Q000235:genetics; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D035381:TATA-Binding Protein Associated Factors / Q000235:genetics / Q000378:metabolism*; D035181:TATA-Box Binding Protein / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015696:Gene Products, tat; D011994:Recombinant Proteins; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D054322:tat Gene Products, Human Immunodeficiency Virus; D005914:Globins
references.citation: Nucleic Acids Res. 1982 Dec 20;10(24):7965-76
references.pmid: 6298703
references.citation: J Exp Med. 1986 Jul 1;164(1):280-90
references.pmid: 3014036
references.citation: Cell. 1986 Sep 26;46(7):973-82
references.pmid: 3530501
references.citation: EMBO J. 1987 May;6(5):1345-53
references.pmid: 2956091
references.citation: Proc Natl Acad Sci U S A. 1987 Sep;84(18):6364-8
references.pmid: 3476953
references.citation: Methods Enzymol. 1987;152:684-704
references.pmid: 3657593
references.citation: Mol Cell Biol. 1987 Aug;7(8):2745-52
references.pmid: 3670292
references.citation: Science. 1987 Nov 6;238(4828):800-2
references.pmid: 3313729
references.citation: Nature. 1987 Dec 3-9;330(6147):489-93
references.pmid: 2825027
references.citation: Cell. 1988 Sep 23;54(7):1043-51
references.pmid: 3416355
references.citation: Nature. 1988 Oct 6;335(6190):563-4
references.pmid: 3047590
references.citation: Nature. 1988 Oct 20;335(6192):683-9
references.pmid: 3050531
references.citation: Nature. 1989 Mar 2;338(6210):39-44
references.pmid: 2521923
references.citation: J Mol Biol. 1999 Oct 22;293(2):235-54
references.pmid: 10550206
references.citation: Methods. 1999 Nov;19(3):425-33
references.pmid: 10579938
references.citation: Microbes Infect. 1999 Sep;1(11):863-9
references.pmid: 10614003
references.citation: Immunity. 2000 Jan;12(1):61-70
references.pmid: 10661406
references.citation: Trends Biochem Sci. 2000 Feb;25(2):59-63
references.pmid: 10664584
references.citation: Gene. 2000 Jan 25;242(1-2):1-13
references.pmid: 10721692
references.citation: Mol Cell Biol. 2000 Apr;20(8):2629-34
references.pmid: 10733565
references.citation: Science. 2000 May 19;288(5469):1242-4
references.pmid: 10817999
references.citation: Science. 2000 May 19;288(5469):1244-8
references.pmid: 10818000
references.citation: Genes Dev. 2000 Oct 15;14(20):2551-69
references.pmid: 11040209
references.citation: Annu Rev Genet. 2000;34:77-137
references.pmid: 11092823
references.citation: Cell. 1981 Dec;27(2 Pt 1):299-308
references.pmid: 6277502
references.citation: Trends Genet. 2001 Aug;17(8):444-8
references.pmid: 11485816
references.citation: Mol Cell Biol. 2002 Jan;22(1):321-31
references.pmid: 11739744
references.citation: Eur J Immunol. 2002 Oct;32(10):2783-91
references.pmid: 12355430
references.citation: J Cell Physiol. 2003 Feb;194(2):101-7
references.pmid: 12494448
references.citation: FEMS Microbiol Lett. 2003 Mar 14;220(1):57-65
references.pmid: 12644228
references.citation: Proc Natl Acad Sci U S A. 2003 Oct 28;100(22):12666-71
references.pmid: 14569024
references.citation: J Cell Physiol. 1977 Sep;92(3):425-36
references.pmid: 903382
references.citation: Cell. 1989 Oct 20;59(2):283-92
references.pmid: 2553266
references.citation: Cell. 1990 Jun 29;61(7):1271-6
references.pmid: 2364429
references.citation: Nature. 1990 Jul 26;346(6282):329-31
references.pmid: 2142753
references.citation: Cell. 1990 Nov 16;63(4):791-802
references.pmid: 2225077
references.citation: Genes Dev. 1990 Dec;4(12A):2061-74
references.pmid: 2269426
references.citation: Genes Dev. 1990 Dec;4(12B):2397-408
references.pmid: 2149119
references.citation: Proc Natl Acad Sci U S A. 1991 May 1;88(9):4045-9
references.pmid: 2023953
references.citation: Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8510-4
references.pmid: 1924310
references.citation: Genes Dev. 1991 Dec;5(12B):2496-507
references.pmid: 1752440
references.citation: Nature. 1993 Mar 11;362(6416):175-9
references.pmid: 7680771
references.citation: Nature. 1993 Mar 11;362(6416):179-81
references.pmid: 8450888
references.citation: J Virol. 1995 Apr;69(4):2605-10
references.pmid: 7884911
references.citation: Annu Rev Biochem. 1996;65:769-99
references.pmid: 8811195
references.citation: Trends Biochem Sci. 1996 Sep;21(9):327-35
references.pmid: 8870495
references.citation: Nature. 1996 Nov 28;384(6607):375-8
references.pmid: 8934526
references.citation: Genes Dev. 1996 Nov 1;10(21):2657-83
references.pmid: 8946909
references.citation: AIDS. 1997 Feb;11(2):139-46
references.pmid: 9030359
references.citation: Nature. 1997 Apr 10;386(6625):569-77
references.pmid: 9121580
references.citation: J Biol Chem. 1998 Feb 27;273(9):5375-84
references.pmid: 9478998
references.citation: Mol Cell. 1998 Jun;1(7):1033-42
references.pmid: 9651586
references.citation: Nucleic Acids Res. 1999 May 15;27(10):2156-64
references.pmid: 10219088
references.citation: Nature. 1999 Jun 10;399(6736):605-9
references.pmid: 10376604
references.citation: Nature. 1999 Jun 10;399(6736):609-13
references.pmid: 10376605
references.citation: Cold Spring Harb Symp Quant Biol. 1998;63:243-52
references.pmid: 10384288
references.citation: Proc Natl Acad Sci U S A. 1999 Jul 6;96(14):7791-6
references.pmid: 10393900
references.citation: Curr Opin Immunol. 1999 Aug;11(4):460-5
references.pmid: 10448148
references.citation: Oncogene. 1999 Aug 12;18(32):4598-605
references.pmid: 10467404
references.citation: Cell. 1989 Oct 20;59(2):229-30
references.pmid: 2680105