scholarly journals Cloning of two proximal sequence element-binding transcription factor subunits (gamma and delta) that are required for transcription of small nuclear RNA genes by RNA polymerases II and III and interact with the TATA-binding protein.

1996 ◽  
Vol 16 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J B Yoon ◽  
R G Roeder
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Binding Protein ◽  
Rna Polymerase Iii ◽  
Class Ii ◽  
Tata Binding Protein ◽  
Small Nuclear Rna ◽  
Sequence Element ◽  
Proximal Sequence Element ◽  
Nuclear Rna

The proximal sequence element (PSE)-binding transcription factor (PTF) specifically recognizes the PSEs of both RNA polymerase II- and RNA polymerase III-transcribed small nuclear RNA (snRNA) genes. We previously have shown that PTF purified from human HeLa cells is a multisubunit complex of four polypeptides designated PTF alpha, -beta, -gamma, and -delta. We now report the isolation and expression of cDNAs encoding PTF gamma and PTF delta, as well as functional studies with cognate antibodies that recognize the native PTF complex in HeLa extracts. Immunoprecipitation studies confirm that the four PTF subunits originally found to copurify during conventional chromatography indeed form a tightly associated complex; they further show that the PTF so defined, including the gamma and delta subunits specifically, is essential for transcription of both class II and class III snRNA genes. Immunoprecipitation assays also show a weak substoichiometric association of the TATA-binding protein (TBP) with PTF, consistent with the previous report of a PTF-related complex (SNAPc) containing substoichiometric levels of TBP and a component (SNAPc43) identical in sequence to the PTF gamma reported here. Glutathione S-transferase pulldown assays further indicate relatively strong direct interactions of both recombinant PTF gamma and PTF delta with TBP, consistent either with the natural association of TBP with PTF in a semistable TBP-TBP-associated factor complex or with possible functional interactions between PSE-bound PTF and TATA-bound TBP during promoter activation. In addition, we show that in extracts depleted of TBP and TBP-associated factors, transcription from the U1 promoter is restored by recombinant TBP but not by TFIID or TFIIIB, indicating that transcription of class II snRNA genes requires a TBP complex different from the one used for mRNA-encoding genes.

Oct-1 and Oct-2 potentiate functional interactions of a transcription factor with the proximal sequence element of small nuclear RNA genes

1992 ◽  
Vol 12 (7) ◽  
pp. 3247-3261
Author(s):  
S Murphy ◽  
J B Yoon ◽  
T Gerster ◽  
R G Roeder
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Polymerase Iii ◽  
Small Nuclear Rna ◽  
Sequence Element ◽  
Proximal Sequence Element ◽  
Pou Domain ◽  
Polymerase Iii ◽  
Nuclear Rna

The promoters of both RNA polymerase II- and RNA polymerase III-transcribed small nuclear RNA (snRNA) genes contain an essential and highly conserved proximal sequence element (PSE) approximately 55 bp upstream from the transcription start site. In addition, the upstream enhancers of all snRNA genes contain binding sites for octamer-binding transcription factors (Octs), and functional studies have indicated that the PSE and octamer elements work cooperatively. The present study has identified and characterized a novel transcription factor (designated PTF) which specifically binds to the PSE sequence of both RNA polymerase II- and RNA polymerase III-transcribed snRNA genes. PTF binding is markedly potentiated by Oct binding to an adjacent octamer site. This potentiation is effected by Oct-1, Oct-2, or the conserved POU domain of these factors. In agreement with these results and despite the independent binding of Octs to the promoter, PTF and Oct-1 enhance transcription from the 7SK promoter in an interdependent manner. Moreover, the POU domain of Oct-1 is sufficient for significant in vitro activity in the presence of PTF. These results suggest that essential activation domains reside in PTF and that the potentiation of PTF binding by Octs plays a key role in the function of octamer-containing snRNA gene enhancers.

scholarly journals Oct-1 and Oct-2 potentiate functional interactions of a transcription factor with the proximal sequence element of small nuclear RNA genes.

1992 ◽  
Vol 12 (7) ◽  
pp. 3247-3261 ◽  
Author(s):  
S Murphy ◽  
J B Yoon ◽  
T Gerster ◽  
R G Roeder
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Polymerase Iii ◽  
Small Nuclear Rna ◽  
Sequence Element ◽  
Proximal Sequence Element ◽  
Pou Domain ◽  
Polymerase Iii ◽  
Nuclear Rna

The promoters of both RNA polymerase II- and RNA polymerase III-transcribed small nuclear RNA (snRNA) genes contain an essential and highly conserved proximal sequence element (PSE) approximately 55 bp upstream from the transcription start site. In addition, the upstream enhancers of all snRNA genes contain binding sites for octamer-binding transcription factors (Octs), and functional studies have indicated that the PSE and octamer elements work cooperatively. The present study has identified and characterized a novel transcription factor (designated PTF) which specifically binds to the PSE sequence of both RNA polymerase II- and RNA polymerase III-transcribed snRNA genes. PTF binding is markedly potentiated by Oct binding to an adjacent octamer site. This potentiation is effected by Oct-1, Oct-2, or the conserved POU domain of these factors. In agreement with these results and despite the independent binding of Octs to the promoter, PTF and Oct-1 enhance transcription from the 7SK promoter in an interdependent manner. Moreover, the POU domain of Oct-1 is sufficient for significant in vitro activity in the presence of PTF. These results suggest that essential activation domains reside in PTF and that the potentiation of PTF binding by Octs plays a key role in the function of octamer-containing snRNA gene enhancers.

scholarly journals Cloning and characterization of the beta subunit of human proximal sequence element-binding transcription factor and its involvement in transcription of small nuclear RNA genes by RNA polymerases II and III.

1996 ◽  
Vol 16 (10) ◽  
pp. 5419-5426 ◽  
Author(s):  
L Bai ◽  
Z Wang ◽  
J B Yoon ◽  
R G Roeder
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Polymerase Iii ◽  
Small Nuclear Rna ◽  
Class Iii ◽  
Sequence Element ◽  
Proximal Sequence Element ◽  
Nuclear Rna

The proximal sequence element (PSE)-binding transcription factor (PTF), which binds the PSE of both RNA polymerase II- and RNA polymerase III-transcribed mammalian small nuclear RNA (snRNA) genes, is essential for their transcription. We previously reported the purification of human PTF, a complex of four subunits, and the molecular cloning and characterization of PTF gamma and delta subunits. Here we describe the isolation and expression of a cDNA encoding PTF beta, as well as functional studies using anti-PTF beta antibodies. Native PTF beta, in either protein fractions or a PTF-Oct-1-DNA complex, can be recognized by polyclonal antibodies raised against recombinant PTF beta. Immunodepletion studies show that PTF beta is required for transcription of both classes of snRNA genes in vitro. In addition, immunoprecipitation analyses demonstrate that substantial and similar molar amounts of TATA-binding protein (TBP) and TFIIIB90 can weakly associate with PTF at low salt conditions, but this association is dramatically reduced at high salt concentrations. Along with our previous demonstration of both physical interactions between PTF gamma/PTF delta and TBP and the involvement of TFIIIB90 in the transcription of class III snRNA genes, these results are consistent with the notion that a TBP-containing complex related to TFIIIB is required for the transcription of class III snRNA genes, and acts through weak interaction with the four-subunit PTF.

scholarly journals Proximal sequence element-binding transcription factor (PTF) is a multisubunit complex required for transcription of both RNA polymerase II- and RNA polymerase III-dependent small nuclear RNA genes.

1995 ◽  
Vol 15 (4) ◽  
pp. 2019-2027 ◽  
Author(s):  
J B Yoon ◽  
S Murphy ◽  
L Bai ◽  
Z Wang ◽  
R G Roeder
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Small Nuclear Rna ◽  
Class Iii ◽  
Sequence Element ◽  
Pol Ii ◽  
Proximal Sequence Element ◽  
Nuclear Rna ◽  
Class Iii Genes ◽  
Pol Iii

The proximal sequence element (PSE), found in both RNA polymerase II (Pol II)- and RNA Pol III-transcribed small nuclear RNA (snRNA) genes, is specifically bound by the PSE-binding transcription factor (PTF). We have purified PTF to near homogeneity from HeLa cell extracts by using a combination of conventional and affinity chromatographic methods. Purified PTF is composed of four polypeptides with apparent molecular masses of 180, 55, 45, and 44 kDa. A combination of preparative electrophoretic mobility shift and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses has conclusively identified these four polypeptides as subunits of human PTF, while UV cross-linking experiments demonstrate that the largest subunit of PTF is in close contact with the PSE. The purified PTF activates transcription from promoters of both Pol II- and Pol III-transcribed snRNA genes in a PSE-dependent manner. In addition, we have investigated factor requirements in transcription of Pol III-dependent snRNA genes. We show that in extracts that have been depleted of TATA-binding protein (TBP) and associated factors, recombinant TBP restores transcription from U6 and 7SK promoters but not from the VAI promoter, whereas the highly purified TBP-TBP-associated factor complex TFIIIB restores transcription from the VAI but not the U6 or 7SK promoter. Furthermore, by complementation of heat-treated extracts lacking TFIIIC activity, we show that TFIIIC1 is required for transcription of both the 7SK and VAI genes, whereas TFIIIC2 is required only for transcription of the VAI gene. From these observations, we conclude (i) that PTF and TFIIIC2 function as gene-specific as gene-specific factors for PSE-and B-box-containing Pol III genes, respectively, (ii) that the form of TBP used by class III genes with upstream promoter elements differs from the from used by class III genes with internal promoters, and (iii) that TFIIIC1 is required for both internal and external Pol III promoters.

scholarly journals Cofractionation of the TATA-binding protein with the RNA polymerase III transcription factor TFIIIB

1992 ◽  
Vol 20 (22) ◽  
pp. 5889-5898 ◽  
Author(s):  
Kenneth A. Simmen ◽  
Jordi Bernues ◽  
Joe D. Lewis ◽  
Lain W. Mattaj
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Binding Protein ◽  
Rna Polymerase Iii ◽  
Tata Binding Protein ◽  
Polymerase Iii

scholarly journals Domains of the Brf component of RNA polymerase III transcription factor IIIB (TFIIIB): functions in assembly of TFIIIB-DNA complexes and recruitment of RNA polymerase to the promoter.

1997 ◽  
Vol 17 (9) ◽  
pp. 5299-5306 ◽  
Author(s):  
G A Kassavetis ◽  
C Bardeleben ◽  
A Kumar ◽  
E Ramirez ◽  
E P Geiduschek
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Binding Protein ◽  
Rna Polymerase Iii ◽  
Tata Binding Protein ◽  
Terminal Segment ◽  
Dna Complexes ◽  
Polymerase Iii ◽  
Transcription Factor Iiib ◽  
Derivatives Of

Saccharomyces cerevisiae transcription factor IIIB (TFIIIB) is composed of three subunits: the TATA-binding protein, the TFIIB-related protein Brf, and B". TFIIIB, which is brought to RNA polymerase III-transcribed genes indirectly through interaction with DNA-bound TFIIIC or directly through DNA recognition by the TATA-binding protein, in turn recruits RNA polymerase III to the promoter. N-terminally deleted derivatives of Brf have been examined for their ability to interact with DNA-bound TFIIIC and with the other components of TFIIIB and for participation in transcription. Brf(165-596), lacking 164 N-proximal TFIIB-homologous amino acids, is competent to participate in the assembly of TFIIIB-DNA complexes and in TFIIIC-independent transcription. Even deletion of the entire TFIIB-homologous half of the protein, as in Brf(317-596) and Brf(352-596), allows some interaction with DNA-bound TBP and with the B" component of TFIIIB to be retained. The function of Brf(165-596) in transcription has also been examined in the context of B" with small internal deletions. The ability of Brf with this sizable N-terminal segment deleted to function in TFIIIC-independent transcription requires segments of B" that are individually indispensable although required on an either/or basis, in the context of complete Brf. These findings suggest a functional complementarity and reciprocity between the Brf and B" components of TFIIIB.

scholarly journals Architectural Arrangement of Cloned Proximal Sequence Element-Binding Protein Subunits on Drosophila U1 and U6 snRNA Gene Promoters

2004 ◽  
Vol 24 (5) ◽  
pp. 1897-1906 ◽  
Author(s):  
Cheng Li ◽  
Gale A. Harding ◽  
Jason Parise ◽  
Kathleen J. McNamara-Schroeder ◽  
William E. Stumph
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Binding Protein ◽  
Rna Polymerase Iii ◽  
Cross Linking ◽  
Gene Promoters ◽  
Sequence Element ◽  
Proximal Sequence Element ◽  
U6 Snrna ◽  
Cloned Gene

ABSTRACT Transcription of snRNA genes by either RNA polymerase II (U1 to U5) or RNA polymerase III (U6) is dependent upon a proximal sequence element (PSE) located approximately 40 to 60 bp upstream of the transcription start site. In Drosophila melanogaster, RNA polymerase specificity is determined by as few as three nucleotide differences within the otherwise well-conserved 21-bp PSE. Previous photo-cross-linking studies revealed that the D. melanogaster PSE-binding protein, DmPBP, contains three subunits (DmPBP45, DmPBP49, and DmPBP95) that associate with the DNA to form complexes that are conformationally distinct depending upon whether the protein is bound to a U1 or a U6 PSE. We have identified and cloned the genes that code for these subunits of DmPBP by virtue of their similarity to three of the five subunits of SNAPc, the human PBP. When expressed in S2 cells, each of the three cloned gene products is incorporated into a protein complex that functionally binds to a PSE. We also find that the conformational difference referred to above is particularly pronounced for DmPBP45, herein identified as the ortholog of human SNAP43. DmPBP45 cross-linked strongly to DNA for two turns of the DNA helix downstream of the U1 PSE, but it cross-linked strongly for only a half turn of the helix downstream of a U6 PSE. These substantial differences in the cross-linking pattern are consistent with those of a model in which conformational differences in DmPBP-DNA complexes lead to selective RNA polymerase recruitment to U1 and U6 promoters.

scholarly journals A Divergent Transcription Factor TFIIB in Trypanosomes Is Required for RNA Polymerase II-Dependent Spliced Leader RNA Transcription and Cell Viability

2006 ◽  
Vol 5 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Jennifer B. Palenchar ◽  
Wenzhe Liu ◽  
Peter M. Palenchar ◽  
Vivian Bellofatto
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Gene Transcription ◽  
Binding Protein ◽  
In Vitro Transcription ◽  
Tata Binding Protein ◽  
Small Nuclear Rna ◽  
Spliced Leader

ABSTRACT Transcription by RNA polymerase II in trypanosomes deviates from the standard eukaryotic paradigm. Genes are transcribed polycistronically and subsequently cleaved into functional mRNAs, requiring trans splicing of a capped 39-nucleotide leader RNA derived from a short transcript, the spliced leader (SL) RNA. The only identified trypanosome RNA polymerase II promoter is that of the SL RNA gene. We have previously shown that transcription of SL RNA requires divergent trypanosome homologs of RNA polymerase II, TATA binding protein, and the small nuclear RNA (snRNA)-activating protein complex. In other eukaryotes, TFIIB is an additional key component of transcription for both mRNAs and polymerase II-dependent snRNAs. We have identified a divergent homolog of the usually highly conserved basal transcription factor, TFIIB, from the pathogenic parasite Trypanosoma brucei. T. brucei TFIIB (TbTFIIB) interacted directly with the trypanosome TATA binding protein and RNA polymerase II, confirming its identity. Functionally, in vitro transcription studies demonstrated that TbTFIIB is indispensable in SL RNA gene transcription. RNA interference (RNAi) studies corroborated the essential nature of TbTFIIB, as depletion of this protein led to growth arrest of parasites. Furthermore, nuclear extracts prepared from parasites depleted of TbTFIIB, after the induction of RNAi, required recombinant TbTFIIB to support spliced leader transcription. The information gleaned from TbTFIIB studies furthers our understanding of SL RNA gene transcription and the elusive overall transcriptional processes in trypanosomes.

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