Structure and Function of the Small Subunit of TFIIF (RAP30) from Drosophilamelanogaster

Abstract

To study the mechanism of basal transcription by RNA polymerase II, a cDNA encoding the Drosophila homologue of the small subunit of TFIIF (also referred to as TFIIF30, RAP30, factor 5b, and γ) was isolated. The Drosophila TFIIF30 gene is located at region 86C on the right arm of the third chromosome. The protein encoded by the cDNA, termed dTFIIF30, was synthesized in Escherichia coli and purified to greater than 95% homogeneity. In reconstituted transcription reactions with purified basal factors, the specific activity of dTFIIF30 was identical to that of its human homologue. Moreover, a carboxyl-terminal fragment, designated dF30(119-276), which contains the carboxyl-terminal 158 amino acid residues of dTFIIF30, was found to possess approximately 50% of the transcriptional activity as full-length dTFIIF30. The interaction of dTFIIF30 with the large subunit of TFIIF (also referred to as TFIIF74, RAP74, factor 5a, and β) was investigated by glycerol gradient sedimentation analyses. In these experiments, dTFIIF30, but not dF30(119-276), assembled into a stable heteromeric complex with TFIIF74. These results, combined with those of previous work on TFIIF, support a model for TFIIF30 function in which the carboxyl-terminal region constitutes a functional domain that can interact with RNA polymerase II to mediate basal transcription, whereas the amino terminus comprises a domain that interacts with TFIIF74. To study the mechanism of basal transcription by RNA polymerase II, a cDNA encoding the Drosophila homologue of the small subunit of TFIIF (also referred to as TFIIF30, RAP30, factor 5b, and γ) was isolated. The Drosophila TFIIF30 gene is located at region 86C on the right arm of the third chromosome. The protein encoded by the cDNA, termed dTFIIF30, was synthesized in Escherichia coli and purified to greater than 95% homogeneity. In reconstituted transcription reactions with purified basal factors, the specific activity of dTFIIF30 was identical to that of its human homologue. Moreover, a carboxyl-terminal fragment, designated dF30(119-276), which contains the carboxyl-terminal 158 amino acid residues of dTFIIF30, was found to possess approximately 50% of the transcriptional activity as full-length dTFIIF30. The interaction of dTFIIF30 with the large subunit of TFIIF (also referred to as TFIIF74, RAP74, factor 5a, and β) was investigated by glycerol gradient sedimentation analyses. In these experiments, dTFIIF30, but not dF30(119-276), assembled into a stable heteromeric complex with TFIIF74. These results, combined with those of previous work on TFIIF, support a model for TFIIF30 function in which the carboxyl-terminal region constitutes a functional domain that can interact with RNA polymerase II to mediate basal transcription, whereas the amino terminus comprises a domain that interacts with TFIIF74. INTRODUCTIONTranscription by RNA polymerase II has a central role in a broad range of biological phenomena, and it is therefore useful to study the proteins that are involved in the basal transcription process (for recent reviews, see (1Buratowski S. Cell. 1994; 77: 1-3Abstract Full Text PDF PubMed Scopus (264) Google Scholar, 2Conaway R.C. Conaway J.W. Annu. Rev. Biochem. 1993; 62: 161-190Crossref PubMed Scopus (344) Google Scholar, 3Drapkin R. Merino A. Reinberg D. Curr. Opin. Cell Biol. 1993; 5: 469-476Crossref PubMed Scopus (65) Google Scholar, 4Zawel L. Reinberg D. Prog. Nucleic Acids Res. Mol. Biol. 1993; 44: 67-108Crossref PubMed Scopus (284) Google Scholar, 5Zawel L. Reinberg D. Annu. Rev. Biochem. 1995; 64 (in press)Crossref PubMed Scopus (389) Google Scholar)). RNA polymerase II, as conventionally defined, is capable of synthesis of RNA from a DNA template, but it additionally requires auxiliary proteins termed the “basal” or “general” factors for accurate and efficient transcription initiation and elongation. The basal factors include transcription factor (TF) ( 1The abbreviations used are: TFtranscription factordTFIIF30the 30-kDa subunit of RNA polymerase II transcription factor IIF, which is also known as RAP30 (RNA polymerase II-associated protein of 30 kDa apparent molecular mass)dF30(119-276)a fusion protein that consists of amino acid residues 119-276 of dTFIIF30 (the carboxyl-terminal 158 amino acid residues of dTFIIF30) with a 21-amino acid residue amino-terminal extension that contains six consecutive histidine residuesPCRpolymerase chain reaction. )IIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, TFIIJ, TFIIS, and SIII. ( 2Transcription factors IIA through IIS are abbreviated as TFIIA, TFIIB, and so on. The TATA box-binding polypeptide of the TFIID complex is referred to as TBP. The purified basal factors used in this study were synthesized in E. coli. A lower case d, r, or h designates the original source of the recombinant factors as either Drosophila, rat, or human, respectively. The 34- and 56-kDa subunits of human TFIIE are referred to as hTFIIE34 and hTFIIE56. The 30- and 74-kDa subunits of human TFIIF are designated as hTFIIF30 and hTFIIF74. Alternate nomenclature for the basal transcription factors (for reviews, see (1Buratowski S. Cell. 1994; 77: 1-3Abstract Full Text PDF PubMed Scopus (264) Google Scholar, 2Conaway R.C. Conaway J.W. Annu. Rev. Biochem. 1993; 62: 161-190Crossref PubMed Scopus (344) Google Scholar, 3Drapkin R. Merino A. Reinberg D. Curr. Opin. Cell Biol. 1993; 5: 469-476Crossref PubMed Scopus (65) Google Scholar, 4Zawel L. Reinberg D. Prog. Nucleic Acids Res. Mol. Biol. 1993; 44: 67-108Crossref PubMed Scopus (284) Google Scholar, 5Zawel L. Reinberg D. Annu. Rev. Biochem. 1995; 64 (in press)Crossref PubMed Scopus (389) Google Scholar)) is as follows: TFIIB (α, FA, factor e); TFIID (τ, factor d, BTF-1); TFIIE (ε, factor a); TFIIF (RAP30/74, βγ, factor 5, FC, BTF-4, factor g); TFIIH (BTF-2, factor b, δ); TFIIS (S-II). )It appears that TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH are involved in the early steps of initiation and promoter clearance, while TFIIF, TFIIJ, TFIIS, and SIII facilitate elongation of the polymerase. It is postulated that the initial steps in the assembly of the transcription complex are the binding of TFIID, TFIIA, and TFIIB to the TATA box and initiation site sequences. Then, TFIIF and RNA polymerase II are incorporated to yield a minimal transcription complex(6Parvin J.D. Sharp P.A. Cell. 1993; 73: 533-540Abstract Full Text PDF PubMed Scopus (307) Google Scholar, 7Tyree C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google the of TFIIE, TFIIH, and is to the basal transcription has in the and of the basal transcription factors, the of basal transcription is at a early and the as this the small 30-kDa subunit of the Drosophila of TFIIF, which TFIIF was and purified by its to to RNA polymerase II and was for RNA polymerase II-associated proteins of 30 and kDa apparent molecular Biol. Full Text PDF PubMed Google Scholar, PubMed Scopus Google Scholar, 5: PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, S. PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, Biol. Full Text PDF PubMed Google Scholar, Biochem. Full Text PDF PubMed Scopus Google Scholar, Biol. 1993; Full Text PDF PubMed Google In TFIIF was as a of a transcription and was found to identical to E. Reinberg D. Biol. Full Text PDF PubMed Google Scholar, E. Reinberg D. Biol. Full Text PDF PubMed Google Scholar, Reinberg D. Biol. Full Text PDF PubMed Google Scholar, Reinberg D. S. A. PubMed Scopus Google TFIIF has also in rat, it is designated J.W. Conaway R.C. Biol. Full Text PDF PubMed Google Scholar, R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, J.W. Conaway R.C. PubMed Scopus Google Scholar, A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google in Drosophila, it is designated factor Biol. Full Text PDF PubMed Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, A. Nucleic Acids Res. 1993; PubMed Scopus Google Scholar, Biol. 1994; Full Text PDF PubMed Google and in it is designated factor Biol. Full Text PDF PubMed Google The cDNA of the encoding the large subunit of TFIIF from A. PubMed Scopus Google Scholar, S. S. PubMed Scopus Google and A. Nucleic Acids Res. 1993; PubMed Scopus Google Scholar, Nucleic Acids Res. 1993; PubMed Scopus Google while the cDNA of the encoding the small subunit of TFIIF from PubMed Scopus Google Scholar, R. Nucleic Acids Res. PubMed Scopus Google A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google and S. Nucleic Acids Res. PubMed Scopus Google of to into the function of In transcription that TFIIF30 is for transcription initiation and of whereas transcriptional elongation and is to for transcription C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google Scholar, Biol. 1993; Full Text PDF PubMed Google Scholar, Biol. 1994; Full Text PDF PubMed Google Scholar, R. Cell. 1994; 77: Full Text PDF PubMed Scopus Google Scholar, S. Conaway R.C. Conaway J.W. Biol. 1994; Full Text PDF PubMed Google The binding of TFIIF to RNA polymerase II is to through a region in TFIIF30 that appears to TFIIF30 and PubMed Scopus Google Scholar, S. PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, Reinberg D. S. A. PubMed Scopus Google Scholar, J.W. Conaway R.C. PubMed Scopus Google The interaction of TFIIF30 with RNA polymerase II the binding of polymerase to Biol. Full Text PDF PubMed Google while subunits of TFIIF polymerase from DNA to which it is J.W. Conaway R.C. PubMed Scopus Google In with TFIIF or a carboxyl-terminal of TFIIF to the that of the carboxyl-terminal amino acid residues of which not with the not the interaction of with but the interaction of with A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google in which of hTFIIF30 and were in that the amino-terminal amino acid residues of hTFIIF30 are for interaction with whereas residues of are for interaction with S. Nucleic Acids Res. 1993; PubMed Scopus Google These to a model TFIIF30 comprises amino-terminal domain that interacts with and a carboxyl-terminal domain that interacts with RNA polymerase II and is for basal this the of a cDNA encoding Drosophila TFIIF30 and the function of the recombinant found that the Drosophila of TFIIF30 is to the human factor and that a carboxyl-terminal of the protein is in its interaction with but functional for basal These that the interaction of TFIIF30 with is from the of TFIIF30 to in basal transcription by RNA polymerase of cDNA region of Drosophila DNA was by with that to of the PubMed Scopus Google Scholar, A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, R. Nucleic Acids Res. PubMed Scopus Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google and S. Nucleic Acids Res. PubMed Scopus Google TFIIF30 cDNA sequences. DNA of the DNA that the region the with amino acid that was to that of These were used to for the of a cDNA by the of a Drosophila cDNA The dTFIIF30 cDNA is in and of site was at the of the dTFIIF30 cDNA by and the was to that not the Then, that contains the dTFIIF30 region was into this dTFIIF30 protein was synthesized in Escherichia coli The protein was purified by the and that was by A. PubMed Scopus Google for the of was purified to apparent as the protein was to on a range at with and the of The protein was in and the was with of the was with a gradient from to and dTFIIF30 at approximately as by the of the The dTFIIF30 were to the of and the was to on a range at with dTFIIF30 from the with a of approximately and the protein was greater than 95% as by and either or with a of of dTFIIF30 was at a of was by the by as a and of dTFIIF30 was by to yield a encoding (in by amino acid residues 119-276 of dTFIIF30, and the was to that not the The was into The protein encoded by this which is termed dF30(119-276), consists of amino acid residues 119-276 of dTFIIF30 (the carboxyl-terminal 158 amino acid residues of dTFIIF30) with a 21-amino acid residue amino-terminal extension that contains six consecutive histidine residues for The protein was purified to by on and by with A of the is of basal transcription factors, and were synthesized in E. coli and purified to greater than as C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google The recombinant that was used in the glycerol gradient sedimentation is termed A. 1993; PubMed Scopus Google of has a carboxyl-terminal extension that contains six consecutive histidine residues and was purified by as by A. 1993; PubMed Scopus Google RNA polymerase IIA was purified to greater than from as by George C.P. Lira-DeVito Mol. Cell. Biol. 1995; PubMed Google and to by glycerol gradient TFIIH from Reinberg D. Biol. Full Text PDF PubMed Google was the of and Reinberg of and of transcription and extension from the Drosophila promoter and the promoter were as in C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google (the of dTFIIF30 and were at for in gradient and of as glycerol and in a of The were the identical in a with of for h at The that were not to with were at for 30 in gradient glycerol to of the was to in a at for h at in a glycerol gradient with of glycerol at the of the from gradient were The were with acid and by on a and with of a cDNA the Drosophila of for the of transcription in Drosophila, a cDNA encoding the Drosophila of the small subunit of with that to of TFIIF30 that were TFIIF30 a of the Drosophila TFIIF30 was used as a to a Drosophila cDNA that contains the The Drosophila homologue of TFIIF30, as from the cDNA is a protein of amino acid residues and a molecular of A of the amino acid of the Drosophila, human, and TFIIF30 proteins 50% and the human and Drosophila factors and and the and Drosophila factors of to factors, which in human, rat, and PubMed Scopus Google Scholar, Biochem. Full Text PDF PubMed Scopus Google Scholar, A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, R. Nucleic Acids Res. PubMed Scopus Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google are also in the Drosophila of with RNA from Drosophila h a of approximately not which with the of the cDNA that dTFIIF30 is encoded by a gene not in to the Drosophila TFIIF30 was to region 86C on the right arm of the third chromosome. ( and of E. the of recombinant dTFIIF30, it was to and the protein and to the activity of the factor in a reconstituted in transcription therefore the to which of the dTFIIF30 cDNA into the E. coli The E. dTFIIF30 was purified to greater than 95% by of E. dTFIIF30 and by The proteins were by molecular of purified dTFIIF30 purified The of the molecular are in the of the recombinant dTFIIF30 to function in a reconstituted transcription These reactions were with recombinant TFIIB, TFIIE, and TFIIF with purified RNA polymerase IIA and DNA that not J.D. Sharp P.A. Cell. 1993; 73: 533-540Abstract Full Text PDF PubMed Scopus (307) Google Scholar, 7Tyree C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google Scholar, R. Cell. 1994; 77: Full Text PDF PubMed Scopus Google Scholar, 1994; PubMed Scopus Google The transcription were to extension these the synthesis of than in In these basal transcription the specific activity of dTFIIF30 with the Drosophila promoter was to that of hTFIIF30 In the activity of dTFIIF30 was identical to that of hTFIIF30 at of factors as as with the promoter not therefore that the dTFIIF30 is to its human for basal dTFIIF30 and are in a reconstituted transcription reactions were in the or of dTFIIF30 with the purified hTFIIE34 and RNA polymerase II The were to extension and the transcription are of dTFIIF30 with the Drosophila promoter of hTFIIF30 dTFIIF30 dTFIIF30 in the of of of dTFIIF30 with the promoter of reactions were with of either dTFIIF30 5, or or 5, or transcription from a DNA reactions were with the promoter of and the purified factors in the or of Reinberg D. Biol. Full Text PDF PubMed Google either dTFIIF30 or was in the of of of the amino acid of the Drosophila and TFIIF30 as in that the of TFIIF30 was the carboxyl-terminal region that to residues of dTFIIF30 and residues of of TFIIF30 comprises the of to factors, which to for with RNA polymerase PubMed Scopus Google Scholar, S. PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, Biochem. Full Text PDF PubMed Scopus Google Scholar, A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, R. Nucleic Acids Res. PubMed Scopus Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google In the of TFIIF30 acid residues of dTFIIF30, and residues of that is amino-terminal to the terminus Drosophila and It therefore that the carboxyl-terminal 158 amino acid residues of dTFIIF30 a functional domain that in to mediate transcription this a of the dTFIIF30, which termed dF30(119-276), that comprises the carboxyl-terminal 158 amino acid residues protein was synthesized in E. coli and purified to greater than 95% the of purified to for dTFIIF30 in reconstituted in transcription with the promoter The of either dTFIIF30 or to the transcription reactions in a in of the transcription with a that the specific activity of was 50% of that of the full-length dTFIIF30 at the of the In as in basal transcription from a DNA TFIIH is 1994; PubMed Scopus Google These that the carboxyl-terminal 158 amino acid residues of dTFIIF30 are for basal transcription by RNA polymerase a with dTFIIF30, but with of the amino acid of Drosophila and TFIIF30 that the amino-terminal region acid residues of dTFIIF30 and residues of is also on the that the amino-terminal amino acid residues of hTFIIF30 are for binding to in in a S. Nucleic Acids Res. 1993; PubMed Scopus Google it that dF30(119-276), which is the amino-terminal amino acid residues of dTFIIF30 but is functional for basal transcription in its interaction with therefore the of the TFIIF subunits by sedimentation of dTFIIF30 and with glycerol the factors were combined in in the that was used in the transcription reactions for 30 at and to glycerol gradient the of the dTFIIF30 not with hTFIIF74. and of the proteins in the assembly of a stable The factors, and in were in a and the was by to of the proteins to glycerol gradient The and of the factors not sedimentation to proteins that were not with not and of dTFIIF30 with in a in the sedimentation of of the dTFIIF30, as it with the in the glycerol it appears that and of dTFIIF30 and is for the efficient assembly of a stable heteromeric gradient sedimentation dTFIIF30 and but not and hTFIIF74. The were in to sedimentation in a glycerol from of the were by and the proteins were by with the protein were to a and in which was to a of and by The of the molecular of are in In the of is a that appears as a with apparent molecular of approximately the sedimentation of protein either or with These that the not with that were identical to those used for dTFIIF30. It therefore appears that dF30(119-276), which is for basal transcription, not a stable complex with hTFIIF74. These combined with that of previous work on TFIIF, in support of a model for TFIIF30 function in which the carboxyl-terminal region constitutes a functional domain that can interact with RNA polymerase II to mediate basal transcription, whereas the amino terminus comprises a domain that interacts with is to that the sedimentation of was not by the of dTFIIF30, it was in a stable complex with dTFIIF30. are for this but it is that the TFIIF complex sedimentation the apparent molecular of TFIIF as by glycerol gradient sedimentation kDa for the Drosophila Mol. Cell. Biol. PubMed Scopus Google is of the as by or kDa for the human or Reinberg D. Biol. Full Text PDF PubMed Google Scholar, J.W. Conaway R.C. Biol. Full Text PDF PubMed Google in the in the sedimentation of dTFIIF30 that it with and of dTFIIF30 with the of a stable heteromeric complex the that with a is for the of a interaction dTFIIF30 and is with the of Biol. 1994; Full Text PDF PubMed Google it was that of hTFIIF30 and and of the TFIIF that has from Drosophila, rat, or human is a with of Reinberg D. Biol. Full Text PDF PubMed Google Scholar, J.W. Conaway R.C. Biol. Full Text PDF PubMed Google Scholar, Mol. Cell. Biol. PubMed Scopus Google it is that the of the factor than the as by Biol. 1994; Full Text PDF PubMed Google with the found that the and protein the transcriptional activity as the not are a for these a of TFIIF30 and not for transcription either in or in TFIIF30 and into the heteromeric in the of the transcription the transcription in not in for a interaction the In this it is that the protein is for basal transcription, but it is to a stable complex with hTFIIF74. a TFIIF30 and not to for transcription in and on the and the function of the Drosophila homologue of the small subunit of The cDNA encoding Drosophila TFIIF30 useful for which include the of the of the protein also dTFIIF30, which are The of dTFIIF30 and that the terminus of the TFIIF30 is for basal transcription, while the amino terminus of the factor is for with a this subunit of TFIIF a polypeptide of a basal transcription complex that greater than TFIIF30 is to function at early in the assembly of the transcription and is a of the central of the minimal transcriptional which comprises TFIIB, TFIIF30, and the polymerase. in of the apparent of the TFIIF has a and role in the transcription reaction. The of the the TFIIF subunits as as the functional TFIIF and the of the transcriptional gene transcription and INTRODUCTIONTranscription by RNA polymerase II has a central role in a broad range of biological phenomena, and it is therefore useful to study the proteins that are involved in the basal transcription process (for recent reviews, see (1Buratowski S. Cell. 1994; 77: 1-3Abstract Full Text PDF PubMed Scopus (264) Google Scholar, 2Conaway R.C. Conaway J.W. Annu. Rev. Biochem. 1993; 62: 161-190Crossref PubMed Scopus (344) Google Scholar, 3Drapkin R. Merino A. Reinberg D. Curr. Opin. Cell Biol. 1993; 5: 469-476Crossref PubMed Scopus (65) Google Scholar, 4Zawel L. Reinberg D. Prog. Nucleic Acids Res. Mol. Biol. 1993; 44: 67-108Crossref PubMed Scopus (284) Google Scholar, 5Zawel L. Reinberg D. Annu. Rev. Biochem. 1995; 64 (in press)Crossref PubMed Scopus (389) Google Scholar)). RNA polymerase II, as conventionally defined, is capable of synthesis of RNA from a DNA template, but it additionally requires auxiliary proteins termed the “basal” or “general” factors for accurate and efficient transcription initiation and elongation. The basal factors include transcription factor (TF) ( 1The abbreviations used are: TFtranscription factordTFIIF30the 30-kDa subunit of RNA polymerase II transcription factor IIF, which is also known as RAP30 (RNA polymerase II-associated protein of 30 kDa apparent molecular mass)dF30(119-276)a fusion protein that consists of amino acid residues 119-276 of dTFIIF30 (the carboxyl-terminal 158 amino acid residues of dTFIIF30) with a 21-amino acid residue amino-terminal extension that contains six consecutive histidine residuesPCRpolymerase chain reaction. )IIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, TFIIJ, TFIIS, and SIII. ( 2Transcription factors IIA through IIS are abbreviated as TFIIA, TFIIB, and so on. The TATA box-binding polypeptide of the TFIID complex is referred to as TBP. The purified basal factors used in this study were synthesized in E. coli. A lower case d, r, or h designates the original source of the recombinant factors as either Drosophila, rat, or human, respectively. The 34- and 56-kDa subunits of human TFIIE are referred to as hTFIIE34 and hTFIIE56. The 30- and 74-kDa subunits of human TFIIF are designated as hTFIIF30 and hTFIIF74. Alternate nomenclature for the basal transcription factors (for reviews, see (1Buratowski S. Cell. 1994; 77: 1-3Abstract Full Text PDF PubMed Scopus (264) Google Scholar, 2Conaway R.C. Conaway J.W. Annu. Rev. Biochem. 1993; 62: 161-190Crossref PubMed Scopus (344) Google Scholar, 3Drapkin R. Merino A. Reinberg D. Curr. Opin. Cell Biol. 1993; 5: 469-476Crossref PubMed Scopus (65) Google Scholar, 4Zawel L. Reinberg D. Prog. Nucleic Acids Res. Mol. Biol. 1993; 44: 67-108Crossref PubMed Scopus (284) Google Scholar, 5Zawel L. Reinberg D. Annu. Rev. Biochem. 1995; 64 (in press)Crossref PubMed Scopus (389) Google Scholar)) is as follows: TFIIB (α, FA, factor e); TFIID (τ, factor d, BTF-1); TFIIE (ε, factor a); TFIIF (RAP30/74, βγ, factor 5, FC, BTF-4, factor g); TFIIH (BTF-2, factor b, δ); TFIIS (S-II). )It appears that TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH are involved in the early steps of initiation and promoter clearance, while TFIIF, TFIIJ, TFIIS, and SIII facilitate elongation of the polymerase. It is postulated that the initial steps in the assembly of the transcription complex are the binding of TFIID, TFIIA, and TFIIB to the TATA box and initiation site sequences. Then, TFIIF and RNA polymerase II are incorporated to yield a minimal transcription complex(6Parvin J.D. Sharp P.A. Cell. 1993; 73: 533-540Abstract Full Text PDF PubMed Scopus (307) Google Scholar, 7Tyree C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google the of TFIIE, TFIIH, and is to the basal transcription has in the and of the basal transcription factors, the of basal transcription is at a early and the as this the small 30-kDa subunit of the Drosophila of TFIIF, which TFIIF was and purified by its to to RNA polymerase II and was for RNA polymerase II-associated proteins of 30 and kDa apparent molecular Biol. Full Text PDF PubMed Google Scholar, PubMed Scopus Google Scholar, 5: PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, S. PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, Biol. Full Text PDF PubMed Google Scholar, Biochem. Full Text PDF PubMed Scopus Google Scholar, Biol. 1993; Full Text PDF PubMed Google In TFIIF was as a of a transcription and was found to identical to E. Reinberg D. Biol. Full Text PDF PubMed Google Scholar, E. Reinberg D. Biol. Full Text PDF PubMed Google Scholar, Reinberg D. Biol. Full Text PDF PubMed Google Scholar, Reinberg D. S. A. PubMed Scopus Google TFIIF has also in rat, it is designated J.W. Conaway R.C. Biol. Full Text PDF PubMed Google Scholar, R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, J.W. Conaway R.C. PubMed Scopus Google Scholar, A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google in Drosophila, it is designated factor Biol. Full Text PDF PubMed Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, A. Nucleic Acids Res. 1993; PubMed Scopus Google Scholar, Biol. 1994; Full Text PDF PubMed Google and in it is designated factor Biol. Full Text PDF PubMed Google The cDNA of the encoding the large subunit of TFIIF from A. PubMed Scopus Google Scholar, S. S. PubMed Scopus Google and A. Nucleic Acids Res. 1993; PubMed Scopus Google Scholar, Nucleic Acids Res. 1993; PubMed Scopus Google while the cDNA of the encoding the small subunit of TFIIF from PubMed Scopus Google Scholar, R. Nucleic Acids Res. PubMed Scopus Google A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google Scholar, S. Nucleic Acids Res. PubMed Scopus Google and S. Nucleic Acids Res. PubMed Scopus Google of to into the function of In transcription that TFIIF30 is for transcription initiation and of whereas transcriptional elongation and is to for transcription C.M. George C.P. Lira-DeVito L. 1993; PubMed Scopus Google Scholar, Biol. 1993; Full Text PDF PubMed Google Scholar, Biol. 1994; Full Text PDF PubMed Google Scholar, R. Cell. 1994; 77: Full Text PDF PubMed Scopus Google Scholar, S. Conaway R.C. Conaway J.W. Biol. 1994; Full Text PDF PubMed Google The binding of TFIIF to RNA polymerase II is to through a region in TFIIF30 that appears to TFIIF30 and PubMed Scopus Google Scholar, S. PubMed Scopus Google Scholar, Mol. Cell. Biol. PubMed Scopus Google Scholar, Reinberg D. S. A. PubMed Scopus Google Scholar, J.W. Conaway R.C. PubMed Scopus Google The interaction of TFIIF30 with RNA polymerase II the binding of polymerase to Biol. Full Text PDF PubMed Google while subunits of TFIIF polymerase from DNA to which it is J.W. Conaway R.C. PubMed Scopus Google In with TFIIF or a carboxyl-terminal of TFIIF to the that of the carboxyl-terminal amino acid residues of which not with the not the interaction of with but the interaction of with A. Conaway R.C. Conaway J.W. Biol. Full Text PDF PubMed Google in which of hTFIIF30 and were in that the amino-terminal amino acid residues of hTFIIF30 are for interaction with whereas residues of are for interaction with S. Nucleic Acids Res. 1993; PubMed Scopus Google These to a model TFIIF30 comprises amino-terminal domain that interacts with and a carboxyl-terminal domain that interacts with RNA polymerase II and is for basal this the of a cDNA encoding Drosophila TFIIF30 and the function of the recombinant found that the Drosophila of TFIIF30 is to the human factor and that a carboxyl-terminal of the protein is in its interaction with but functional for basal These that the interaction of TFIIF30 with is from the of TFIIF30 to in basal transcription by RNA polymerase