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Popova VV, Orlova AV, Kurshakova MM, Nikolenko JV, Nabirochkina EN, Georgieva SG, Kopytova DV. The role of SAGA coactivator complex in snRNA transcription. Cell Cycle 2018; 17:1859-1870. [PMID: 29995556 DOI: 10.1080/15384101.2018.1489175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The general snRNA gene transcription apparatus has been extensively studied. However, the role of coactivators in this process is far from being clearly understood. Here, we have demonstrated that the Drosophila SAGA complex interacts with the PBP complex, the key component of the snRNA gene transcription apparatus, and is present at the promoter regions of the snRNA genes transcribed by both the RNA polymerase II and RNA polymerase III (U6 snRNA). We show that SAGA interacts with the Brf1 transcription factor, which is a part of the RNA polymerase III transcription apparatus and is present at promoters of a number of Pol III-transcribed genes. Mutations inactivating several SAGA subunit genes resulted in reduced snRNA levels in adult flies, indicating that SAGA is indeed the transcriptional coactivator for the snRNA genes. The transcription of the Pol II and Pol III-transcribed U genes was reduced by mutations in all tested SAGA complex subunits. Therefore, the transcription of the Pol II and Pol III-transcribed U genes was reduced by the mutations in the deubiquitinase module, as well as in the acetyltransferase module of the SAGA, indicating that the whole complex is essential for their transcription. Therefore, the SAGA complex activates snRNA genes suggesting its wide involvement in the regulation of gene transcription, and consequently, in the maintenance of cellular homeostasis.
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Affiliation(s)
- V V Popova
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - A V Orlova
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - M M Kurshakova
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - J V Nikolenko
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - E N Nabirochkina
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - S G Georgieva
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - D V Kopytova
- a Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
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2
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Verma N, Hung KH, Kang JJ, Barakat NH, Stumph WE. Differential utilization of TATA box-binding protein (TBP) and TBP-related factor 1 (TRF1) at different classes of RNA polymerase III promoters. J Biol Chem 2013; 288:27564-27570. [PMID: 23955442 DOI: 10.1074/jbc.c113.503094] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In the fruit fly Drosophila melanogaster, RNA polymerase III transcription was found to be dependent not upon the canonical TATA box-binding protein (TBP) but instead upon the TBP-related factor 1 (TRF1) (Takada, S., Lis, J. T., Zhou, S., and Tjian, R. (2000) Cell 101, 459-469). Here we confirm that transcription of fly tRNA genes requires TRF1. However, we unexpectedly find that U6 snRNA gene promoters are occupied primarily by TBP in cells and that knockdown of TBP, but not TRF1, inhibits U6 transcription in cells. Moreover, U6 transcription in vitro effectively utilizes TBP, whereas TBP cannot substitute for TRF1 to promote tRNA transcription in vitro. Thus, in fruit flies, different classes of RNA polymerase III promoters differentially utilize TBP and TRF1 for the initiation of transcription.
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Affiliation(s)
- Neha Verma
- Molecular Biology Institute; Departments of Biology
| | - Ko-Hsuan Hung
- Molecular Biology Institute; Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030
| | - Jin Joo Kang
- Molecular Biology Institute; Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030
| | - Nermeen H Barakat
- Molecular Biology Institute; Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030
| | - William E Stumph
- Molecular Biology Institute; Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030.
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3
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Vierna J, Jensen KT, Martínez-Lage A, González-Tizón AM. The linked units of 5S rDNA and U1 snDNA of razor shells (Mollusca: Bivalvia: Pharidae). Heredity (Edinb) 2011; 107:127-42. [PMID: 21364693 DOI: 10.1038/hdy.2010.174] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The linkage between 5S ribosomal DNA and other multigene families has been detected in many eukaryote lineages, but whether it provides any selective advantage remains unclear. In this work, we report the occurrence of linked units of 5S ribosomal DNA (5S rDNA) and U1 small nuclear DNA (U1 snDNA) in 10 razor shell species (Mollusca: Bivalvia: Pharidae) from four different genera. We obtained several clones containing partial or complete repeats of both multigene families in which both types of genes displayed the same orientation. We provide a comprehensive collection of razor shell 5S rDNA clones, both with linked and nonlinked organisation, and the first bivalve U1 snDNA sequences. We predicted the secondary structures and characterised the upstream and downstream conserved elements, including a region at -25 nucleotides from both 5S rDNA and U1 snDNA transcription start sites. The analysis of 5S rDNA showed that some nontranscribed spacers (NTSs) are more closely related to NTSs from other species (and genera) than to NTSs from the species they were retrieved from, suggesting birth-and-death evolution and ancestral polymorphism. Nucleotide conservation within the functional regions suggests the involvement of purifying selection, unequal crossing-overs and gene conversions. Taking into account this and other studies, we discuss the possible mechanisms by which both multigene families could have become linked in the Pharidae lineage. The reason why 5S rDNA is often found linked to other multigene families seems to be the result of stochastic processes within genomes in which its high copy number is determinant.
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Affiliation(s)
- J Vierna
- Department of Molecular and Cell Biology, Evolutionary Biology Group (GIBE), Universidade da Coruña, La Coruña, Spain.
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4
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Hung KH, Titus M, Chiang SC, Stumph WE. A map of Drosophila melanogaster small nuclear RNA-activating protein complex (DmSNAPc) domains involved in subunit assembly and DNA binding. J Biol Chem 2009; 284:22568-79. [PMID: 19556241 DOI: 10.1074/jbc.m109.027961] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription of genes coding for the small nuclear RNAs (snRNAs) is dependent upon a unique transcription factor known as the small nuclear RNA-activating protein complex (SNAPc). SNAPc binds to an essential proximal sequence element located about 40-65 base pairs upstream of the snRNA transcription start site. In the fruit fly Drosophila melanogaster, DmSNAPc contains three distinct polypeptides (DmSNAP190, DmSNAP50, and DmSNAP43) that are stably associated with each other and bind to the DNA as a complex. We have used mutational analysis to identify domains within each subunit that are involved in complex formation with the other two subunits in vivo. We have also identified domains in each subunit required for sequence-specific DNA binding. With one exception, domains required for subunit-subunit interactions lie in the most evolutionarily conserved regions of the proteins. However, DNA binding by DmSNAPc is dependent not only upon the conserved regions but is also highly dependent upon domains outside the conserved regions. Comparison with functional domains identified in human SNAPc indicates many parallels but also reveals significant differences in this ancient yet rapidly evolving system.
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Affiliation(s)
- Ko-Hsuan Hung
- Molecular Biology Institute, Department of Biology, San Diego State University, San Diego, California 92182-1030, USA
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5
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Hernandez G, Valafar F, Stumph WE. Insect small nuclear RNA gene promoters evolve rapidly yet retain conserved features involved in determining promoter activity and RNA polymerase specificity. Nucleic Acids Res 2006; 35:21-34. [PMID: 17148477 PMCID: PMC1761439 DOI: 10.1093/nar/gkl982] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In animals, most small nuclear RNAs (snRNAs) are synthesized by RNA polymerase II (Pol II), but U6 snRNA is synthesized by RNA polymerase III (Pol III). In Drosophila melanogaster, the promoters for the Pol II-transcribed snRNA genes consist of approximately 21 bp PSEA and approximately 8 bp PSEB. U6 genes utilize a PSEA but have a TATA box instead of the PSEB. The PSEAs of the two classes of genes bind the same protein complex, DmSNAPc. However, the PSEAs that recruit Pol II and Pol III differ in sequence at a few nucleotide positions that play an important role in determining RNA polymerase specificity. We have now performed a bioinformatic analysis to examine the conservation and divergence of the snRNA gene promoter elements in other species of insects. The 5' half of the PSEA is well-conserved, but the 3' half is divergent. Moreover, within each species positions exist where the PSEAs of the Pol III-transcribed genes differ from those of the Pol II-transcribed genes. Interestingly, the specific positions vary among species. Nevertheless, we speculate that these nucleotide differences within the 3' half of the PSEA act similarly to induce conformational alterations in DNA-bound SNAPc that result in RNA polymerase specificity.
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Affiliation(s)
- Genaro Hernandez
- Department of Chemistry and Biochemistry, San Diego State University5500 Campanile Drive, San Diego, CA 92182-1030, USA
- Department of Computer Science, San Diego State University5500 Campanile Drive, San Diego, CA 92182-1030, USA
| | - Faramarz Valafar
- Department of Computer Science, San Diego State University5500 Campanile Drive, San Diego, CA 92182-1030, USA
| | - William E. Stumph
- Department of Chemistry and Biochemistry, San Diego State University5500 Campanile Drive, San Diego, CA 92182-1030, USA
- To whom correspondence should be addressed. Tel: +1 619 594 5575; Fax: +1 619 594-4634;
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Lai HT, Chen H, Li C, McNamara-Schroeder KJ, Stumph WE. The PSEA promoter element of the Drosophila U1 snRNA gene is sufficient to bring DmSNAPc into contact with 20 base pairs of downstream DNA. Nucleic Acids Res 2005; 33:6579-86. [PMID: 16314318 PMCID: PMC1292993 DOI: 10.1093/nar/gki972] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Most of the major spliceosomal small nuclear RNAs (snRNAs) (i.e. U1, U2, U4 and U5) are synthesized by RNA polymerase II (pol II). In Drosophila melanogaster, the 5'-flanking DNA of these genes contains two conserved elements: the proximal sequence element A (PSEA) and the proximal sequence element B (PSEB). The PSEA is essential for transcription and is recognized by DmSNAPc, a multi-subunit protein complex. Previous site-specific protein-DNA photo-cross-linking assays demonstrated that one of the subunits of DmSNAPc, DmSNAP43, remains in close contact with the DNA for 20 bp beyond the 3' end of the PSEA, a region that contains the PSEB. The current work demonstrates that mutation of the PSEB does not abolish the cross-linking of DmSNAP43 to the PSEB. Thus the U1 PSEA alone is capable of bringing DmSNAP43 into close contact with this downstream DNA. However, mutation of the PSEB perturbs the cross-linking pattern. In concordance with these findings, PSEB mutations result in a 2- to 4-fold reduction in U1 promoter activity when assayed by transient transfection.
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Affiliation(s)
| | | | - Cheng Li
- Department of Chemistry and Biochemistry, San Diego State UniversitySan Diego, CA 92182-1030, USA
| | | | - William E. Stumph
- Department of Chemistry and Biochemistry, San Diego State UniversitySan Diego, CA 92182-1030, USA
- To whom correspondence should be addressed. Tel: +1 619 594 5575; Fax: +1 619 594 4634;
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7
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Li C, Harding GA, Parise J, McNamara-Schroeder KJ, Stumph WE. Architectural arrangement of cloned proximal sequence element-binding protein subunits on Drosophila U1 and U6 snRNA gene promoters. Mol Cell Biol 2004; 24:1897-906. [PMID: 14966271 PMCID: PMC350556 DOI: 10.1128/mcb.24.5.1897-1906.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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 SNAP(c), 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.
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Affiliation(s)
- Cheng Li
- Department of Chemistry and Molecular Biology Institute, San Diego State University, San Diego, California 92182-1030, USA
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8
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Hamada M, Huang Y, Lowe TM, Maraia RJ. Widespread use of TATA elements in the core promoters for RNA polymerases III, II, and I in fission yeast. Mol Cell Biol 2001; 21:6870-81. [PMID: 11564871 PMCID: PMC99864 DOI: 10.1128/mcb.21.20.6870-6881.2001] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In addition to directing transcription initiation, core promoters integrate input from distal regulatory elements. Except for rare exceptions, it has been generally found that eukaryotic tRNA and rRNA genes do not contain TATA promoter elements and instead use protein-protein interactions to bring the TATA-binding protein (TBP), to the core promoter. Genomewide analysis revealed TATA elements in the core promoters of tRNA and 5S rRNA (Pol III), U1 to U5 snRNA (Pol II), and 37S rRNA (Pol I) genes in Schizosaccharomyces pombe. Using tRNA-dependent suppression and other in vivo assays, as well as in vitro transcription, we demonstrated an obligatory requirement for upstream TATA elements for tRNA and 5S rRNA expression in S. pombe. The Pol III initiation factor Brf is found in complexes with TFIIIC and Pol III in S. pombe, while TBP is not, consistent with independent recruitment of TBP by TATA. Template commitment assays are consistent with this and confirm that the mechanisms of transcription complex assembly and initiation by Pol III in S. pombe differ substantially from those in other model organisms. The results were extended to large-rRNA synthesis, as mutation of the TATA element in the Pol I promoter also abolishes rRNA expression in fission yeast. A survey of other organisms' genomes reveals that a substantial number of eukaryotes may use widespread TATAs for transcription. These results indicate the presence of TATA-unified transcription systems in contemporary eukaryotes and provide insight into the residual need for TBP by all three Pols in other eukaryotes despite a lack of TATA elements in their promoters.
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MESH Headings
- Amino Acid Motifs
- Amino Acid Sequence
- Base Sequence
- Conserved Sequence
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Evolution, Molecular
- Genome, Fungal
- Immunoblotting
- Molecular Sequence Data
- Promoter Regions, Genetic
- RNA Polymerase I/genetics
- RNA Polymerase I/metabolism
- RNA Polymerase II/genetics
- RNA Polymerase II/metabolism
- RNA Polymerase III/genetics
- RNA Polymerase III/metabolism
- RNA, Ribosomal/metabolism
- RNA, Ribosomal, 5S/genetics
- RNA, Transfer/metabolism
- Schizosaccharomyces/metabolism
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- TATA-Box Binding Protein
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription, Genetic
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Affiliation(s)
- M Hamada
- Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-2753, USA
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9
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Zhou D, Lobo-Ruppert SM. Transcription of the Schizosaccharomyces pombe U2 gene in vivo and in vitro is directed by two essential promoter elements. Nucleic Acids Res 2001; 29:2003-11. [PMID: 11353068 PMCID: PMC55464 DOI: 10.1093/nar/29.10.2003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
As compared to the metazoan small nuclear RNAs (snRNAs), relatively little is known about snRNA synthesis in unicellular organisms. We have analyzed the transcription of the Schizosaccharomyces pombe U2 snRNA gene in vivo and in the homologous in vitro system. Deletion and linker-scanning analyses show that the S.pombe U2 promoter contains at least two elements: the spUSE centered at -55, which functions as an activator, and a TATA box at -26, which is essential for basal transcription. These data point to a similar architecture among S.pombe, plant and invertebrate snRNA promoters. Factors recognizing the spUSE can be detected in whole cell extracts by DNase I footprinting and competition studies show that the binding of these factors correlates with transcriptional activity. Electrophoretic mobility shift assays and gel-filtration chromatography revealed a native molecular mass of approximately 200 kDa for the spUSE binding activity. Two polypeptides of molecular masses 25 and 65 kDa were purified by virtue of their ability to specifically bind the spUSE.
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Affiliation(s)
- D Zhou
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 844 BBRB, 845 19th Street South, Birmingham, AL 35294, USA
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10
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Hardin SB, Ortler CJ, McNamara-Schroeder KJ, Stumph WE. Similarities and differences in the conformation of protein-DNA complexes at the U1 and U6 snRNA gene promoters. Nucleic Acids Res 2000; 28:2771-8. [PMID: 10908334 PMCID: PMC102643 DOI: 10.1093/nar/28.14.2771] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Most small nuclear RNAs (snRNAs) are synthesized by RNA polymerase II, but U6 snRNA is synthesized by RNA polymerase III. In the fruit fly Drosophila melanogaster the RNA polymerase specificity of the snRNA genes is determined by a few nucleotide differences within the proximal sequence element (PSE), a conserved sequence located approximately 40-65 bp upstream of the transcription start site. The PSE is essential for transcription of both RNA polymerase II-transcribed and RNA polymerase III-transcribed snRNA genes and is recognized in Drosophila by a multi-subunit protein factor termed DM:PBP. Previous studies that employed site-specific protein-DNA photocrosslinking indicated that the conformation of the DNA-protein complex is different depending upon whether DM:PBP is bound to a U1 or U6 PSE sequence. These conformational differences of the complex probably represent an early step in determining the selection of the correct RNA polymerase. We have now obtained evidence that DM:PBP modestly bends the DNA upon interacting with the PSE and that the direction of DNA bending is similar for both the U1 and U6 PSEs. Under the assumption that DM:PBP does not significantly twist the DNA, the direction of the bend in both cases is toward the face of the DNA helix contacted by the 45 kDa subunit of DM:PBP. Together with data from partial proteolysis assays, these results indicate that the conformational differences in the complexes of DM:PBP with the U1 and U6 PSEs more likely occur at the protein level rather than at the DNA level.
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Affiliation(s)
- S B Hardin
- Department of Chemistry and Molecular Biology Institute, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1030, USA
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11
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Wang Y, Stumph WE. Identification and topological arrangement of Drosophila proximal sequence element (PSE)-binding protein subunits that contact the PSEs of U1 and U6 small nuclear RNA genes. Mol Cell Biol 1998; 18:1570-9. [PMID: 9488474 PMCID: PMC108872 DOI: 10.1128/mcb.18.3.1570] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Most small nuclear RNAs (snRNAs) are synthesized by RNA polymerase II, but U6 and a few others are synthesized by RNA polymerase III. Transcription of snRNA genes by either polymerase is dependent on a proximal sequence element (PSE) located upstream of position -40 relative to the transcription start site. In contrast to findings in vertebrates, sea urchins, and plants, the RNA polymerase specificity of Drosophila snRNA genes is intrinsically encoded in the PSE sequence itself. We have investigated the differential interaction of the Drosophila melanogaster PSE-binding protein (DmPBP) with U1 and U6 gene PSEs. By using a site specific protein-DNA photo-cross-linking assay, we identified three polypeptide subunits of DmPBP with apparent molecular masses of 95, 49, and 45 kDa that are in close proximity to the DNA and two additional putative polypeptides of 230 and 52 kDa that may be integral to the complex. The 95-kDa subunit cross-linked at positions spanning the entire length of the PSE, but the 49- and 45-kDa subunits cross-linked only to the 3' half of the PSE. The same polypeptides cross-linked to both the U1 and U6 PSE sequences. However, there were significant differences in the cross-linking patterns of these subunits at a subset of the phosphate positions, depending on whether binding was to a U1 or U6 gene PSE. These data suggest that RNA polymerase specificity is associated with distinct modes of interaction of DmPBP with the DNA at U1 and U6 promoters.
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Affiliation(s)
- Y Wang
- Department of Chemistry and Molecular Biology Institute, San Diego State University, California 92182-1030, USA
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12
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Jensen RC, Wang Y, Hardin SB, Stumph WE. The proximal sequence element (PSE) plays a major role in establishing the RNA polymerase specificity of Drosophila U-snRNA genes. Nucleic Acids Res 1998; 26:616-22. [PMID: 9421524 PMCID: PMC147272 DOI: 10.1093/nar/26.2.616] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Most small nuclear RNA (snRNA) genes are transcribed by RNA polymerase II, but some (e.g., U6) are transcribed by RNA polymerase III. In vertebrates a TATA box at a fixed distance downstream of the proximal sequence element (PSE) acts as a dominant determinant for recruiting RNA polymerase III to U6 gene promoters. In contrast, vertebrate snRNA genes that contain a PSE but lack a TATA box are transcribed by RNA polymerase II. In plants, transcription of both classes of snRNA genes requires a TATA box in addition to an upstream sequence element (USE), and polymerase specificity is determined by the spacing between these two core promoter elements. In these examples, the PSE (or USE) is interchangeable between the two classes of snRNA genes. Here we report the surprising finding that the Drosophila U1 and U6 PSEs cannot functionally substitute for each other; rather, determination of RNA polymerase specificity is an intrinsic property of the PSE sequence itself. The alteration of two or three base pairs near the 3'-end of the U1 and U6 PSEs was sufficient to switch the RNA polymerase specificity of Drosophila snRNA promoters in vitro. These findings reveal a novel mechanism for achieving RNA polymerase specificity at insect snRNA promoters.
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Affiliation(s)
- R C Jensen
- Department of Chemistry and Molecular Biology Institute, San Diego State University, San Diego, CA 92182-1030, USA
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13
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Wang Y, Jensen RC, Stumph WE. Role of TATA box sequence and orientation in determining RNA polymerase II/III transcription specificity. Nucleic Acids Res 1996; 24:3100-6. [PMID: 8760900 PMCID: PMC146060 DOI: 10.1093/nar/24.15.3100] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Work from a number of laboratories has indicated that the TATA box sequence can act as a basal promoter element not only for RNA polymerase II (RNAP II) transcription, but also for transcription by RNA polymerase III (RNAP III). We previously reported that, in the absence of other cis-acting elements, the canonical TATA sequence TATAAAAA specifically supported transcription by RNAP II in an unfractionated Drosophila nuclear extract, whereas the sequence TTTTTATA (the same sequence in reverse orientation) directed RNAP III transcription. We have now examined a variety of other TATA box sequences with regard to RNA polymerase selectivity and their ability to support RNAP III transcription. The results have allowed us to rank these TATA box sequences with respect to their relative strengths as RNAP III promoter elements in unfractionated Drosophila extracts. Further, the data indicate that T residues at positions 2 and 4 of the TATA box appear to be important determinants of RNAP III selectivity in this system, whereas A residues at these positions favor RNAP II transcription. Finally, the data suggest that transcription factors TFIID and TFIIIB, although both capable of binding a variety of TATA elements, have distinct sequence preferences for recognizing the TATA box and possibly the surrounding DNA.
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Affiliation(s)
- Y Wang
- Department of Chemistry, San Diego State University, CA 92182-1030, USA
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14
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Wang Y, Stumph WE. RNA polymerase II/III transcription specificity determined by TATA box orientation. Proc Natl Acad Sci U S A 1995; 92:8606-10. [PMID: 7567983 PMCID: PMC41015 DOI: 10.1073/pnas.92.19.8606] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The TATA box sequence in eukaryotes is located about 25 bp upstream of many genes transcribed by RNA polymerase II (Pol II) and some genes transcribed by RNA polymerase III (Pol III). The TATA box is recognized in a sequence-specific manner by the TATA box-binding protein (TBP), an essential factor involved in the initiation of transcription by all three eukaryotic RNA polymerases. We have investigated the recognition of the TATA box by the Pol II and Pol III basal transcription machinery and its role in establishing the RNA polymerase specificity of the promoter. Artificial templates were constructed that contained a canonical TATA box as the sole promoter element but differed in the orientation of the 8-bp TATA box sequence. As expected, Pol II initiated transcription in unfractionated nuclear extracts downstream of the "forward" TATA box. In distinct contrast, transcription that initiated downstream of the "reverse" TATA box was carried out specifically by Pol III. Importantly, this effect was observed regardless of the source of the DNA either upstream or downstream of the TATA sequence. These findings suggest that TBP may bind in opposite orientations on Pol II and Pol III promoters and that opposite, yet homologous, surfaces of TBP may be utilized by the Pol II and Pol III basal machinery for the initiation of transcription.
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Affiliation(s)
- Y Wang
- Department of Chemistry, San Diego State University, CA 92182-1030, USA
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15
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Small nuclear RNA genes transcribed by either RNA polymerase II or RNA polymerase III in monocot plants share three promoter elements and use a strategy to regulate gene expression different from that used by their dicot plant counterparts. Mol Cell Biol 1994. [PMID: 8065324 DOI: 10.1128/mcb.14.9.5910] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA polymerase (Pol) II- and RNA Pol III-transcribed small nuclear RNA (snRNA) genes of dicotyledonous plants contain two essential upstream promoter elements, the USE and TATA. The USE is a highly conserved plant snRNA gene-specific element, and its distance from the -30 TATA box, corresponding to approximately three and four helical DNA turns in Pol III and Pol II genes, respectively, is crucial for determining RNA Pol specificity of transcription. Sequences upstream of the USE play no role in snRNA gene transcription in dicot plants. Here we show that for expression of snRNA genes in maize, a monocotyledonous plant, the USE and TATA elements are essential, but not sufficient, for transcription. Efficient expression of both Pol II- and Pol III-specific snRNA genes in transfected maize protoplasts requires an additional element(s) positioned upstream of the USE. This element, named MSP (for monocot-specific promoter; consensus, RGCCCR), is present in one to three copies in monocot snRNA genes and is interchangeable between Pol II- and Pol III-specific genes. The efficiency of snRNA gene expression in maize protoplast is determined primarily by the strength of the MSP element(s); this contrasts with the situation in protoplasts of a dicot plant, Nicotiana plumbaginifolia, where promoter strength is a function of the quality of the USE element. Interestingly, the organization of monocot Pol III-specific snRNA gene promoters closely resembles those of equivalent vertebrate promoters. The data are discussed in the context of the coevolution of Pol II- and Pol III-specific snRNA gene promoters within many eukaryotic organisms.
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Connelly S, Marshallsay C, Leader D, Brown JW, Filipowicz W. Small nuclear RNA genes transcribed by either RNA polymerase II or RNA polymerase III in monocot plants share three promoter elements and use a strategy to regulate gene expression different from that used by their dicot plant counterparts. Mol Cell Biol 1994; 14:5910-9. [PMID: 8065324 PMCID: PMC359117 DOI: 10.1128/mcb.14.9.5910-5919.1994] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
RNA polymerase (Pol) II- and RNA Pol III-transcribed small nuclear RNA (snRNA) genes of dicotyledonous plants contain two essential upstream promoter elements, the USE and TATA. The USE is a highly conserved plant snRNA gene-specific element, and its distance from the -30 TATA box, corresponding to approximately three and four helical DNA turns in Pol III and Pol II genes, respectively, is crucial for determining RNA Pol specificity of transcription. Sequences upstream of the USE play no role in snRNA gene transcription in dicot plants. Here we show that for expression of snRNA genes in maize, a monocotyledonous plant, the USE and TATA elements are essential, but not sufficient, for transcription. Efficient expression of both Pol II- and Pol III-specific snRNA genes in transfected maize protoplasts requires an additional element(s) positioned upstream of the USE. This element, named MSP (for monocot-specific promoter; consensus, RGCCCR), is present in one to three copies in monocot snRNA genes and is interchangeable between Pol II- and Pol III-specific genes. The efficiency of snRNA gene expression in maize protoplast is determined primarily by the strength of the MSP element(s); this contrasts with the situation in protoplasts of a dicot plant, Nicotiana plumbaginifolia, where promoter strength is a function of the quality of the USE element. Interestingly, the organization of monocot Pol III-specific snRNA gene promoters closely resembles those of equivalent vertebrate promoters. The data are discussed in the context of the coevolution of Pol II- and Pol III-specific snRNA gene promoters within many eukaryotic organisms.
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Affiliation(s)
- S Connelly
- Friedrich Miescher Institute, Basel, Switzerland
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