The in vitro transcription of the 7SK RNA gene by RNA polymerase III is dependent only on the presence of an upstream promoter

Murphy, Shona; Melli, Marialuisa

doi:10.1016/0092-8674(87)90012-2

Cited by 190 publications

(106 citation statements)

References 19 publications

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“…Thus, sequences upstream of the initiation site are necessary and sufficient for 7SK and MRP gene transcription, in contrast to the internal promoters found in most pol III templates (Murphy et al, 1987;Yuan and Reddy, 1991). This results in distinct factor requirements (reviewed by Geiduschek and Kassavetis, 2001;Schramm and Hernandez, 2002).…”

Section: Variable Expression In Cervical Cells Of Mrnas Encoding Tfiimentioning

confidence: 99%

Deregulation of RNA polymerase III transcription in cervical epithelium in response to high-risk human papillomavirus

et al. 2004

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RNA polymerase (pol) III transcription is a major determinant of biosynthetic capacity, providing essential products such as tRNA and 5S rRNA. It is controlled directly by the tumour suppressors RB and p53. High-risk types of human papillomavirus (HPV), such as HPV16, express the oncoproteins E6 and E7 that can inactivate p53 and RB, respectively. Accordingly, both E6 and E7 stimulate pol III transcription in cultured cells. HPV16-positive cervical biopsies express elevated levels of tRNA and 5S rRNA when compared to biopsies that test negative for HPV or are infected with the lower risk HPV11. Integration of viral DNA into the host cell genome stimulates expression of E6 and E7 and correlates with induction of tRNA and 5S rRNA. Expression of mRNA encoding the pol III-specific transcription factor Brf1 also correlates with the presence of integrated HPV16. Brf1 levels are limiting for tRNA and 5S rRNA synthesis in cervical cells. Furthermore, pol III-transcribed genes that do not use Brf1 are not induced in HPV16-positive biopsies. Three complementary mechanisms may therefore allow high-risk HPV to stimulate production of tRNA and 5S rRNA: E6-mediated removal of p53; E7-mediated neutralization of RB; and induction of Brf1. The resultant increase in biosynthetic capacity may contribute to deregulated cell growth.

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Section: Variable Expression In Cervical Cells Of Mrnas Encoding Tfiimentioning

confidence: 99%

Deregulation of RNA polymerase III transcription in cervical epithelium in response to high-risk human papillomavirus

et al. 2004

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“…The DSE contains at least one copy of the octamer motif and functions as an upstream enhancer, whereas the PSE is an essential promoter element which functions in start site selection and may be required for accurate 3Ј-end formation (17,33,35). The promoters of class III snRNA genes (e.g., 7SK and U6) are located solely in the 5Ј-flanking region and lack intragenic control elements typical of most other class III genes (9,29). Like their class II snRNA gene counterparts, class III snRNA genes have similar DSE and PSE configurations but additionally contain a TATA-like sequence at position Ϫ25.…”

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confidence: 99%

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

Yoon

Murphy

Bai

et al. 1995

Molecular and Cellular Biology

121

133

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The proximal sequence element (PSE), found in both RNA polymerase II (Pol II)-and RNA Pol IIItranscribed 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-TBPassociated 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 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 form used by class III genes with internal promoters, and (iii) that TFIIIC1 is required for both internal and external Pol III promoters.Mammalian small nuclear RNA (snRNA) genes contain related promoter structures, but some (class II) are transcribed by RNA polymerase II (Pol II), whereas others (class III) are transcribed by RNA Pol III (reviewed in references 8, 15, 23, 30, and 37). Class II snRNA genes (e.g., U1 to U5) contain two regulatory elements in the 5Ј-flanking region: a distal sequence element (DSE) located approximately 220 bp upstream of the transcription start site, and a proximal sequence element (PSE) centered around Ϫ55. The DSE contains at least one copy of the octamer motif and functions as an upstream enhancer, whereas the PSE is an essential promoter element which functions in start site selection and may be required for accurate 3Ј-end formation (17,33,35). The promoters of class III snRNA genes (e.g., 7SK and U6) are located solely in the 5Ј-flanking region and lack intragenic control elements typical of most other class III genes (9, 29). Like their class II snRNA gene counterparts, class III snRNA genes have similar DSE and PSE configurations but additionally contain a TATA-like sequen...

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“…In addition, the fact that the U6 maxigene is efficiently transcribed in a HeLa S100 extract (results not shown) eliminates the continuity of sequence across nucleotide + 87 as important for transcription. No internal sequences of the human 7SK RNA gene are required for in vitro transcription by polymerase III (Murphy et al 1987a).…”

mentioning

confidence: 99%

“…The deletion analyses carried out in the present study uncovered distal elements that would have masked a transcriptional effect by the TATA sequence. Mutation of the TATA sequence in the Xenopus U6 gene results in a minor reduction of U6 synthesis in injected oocytes , whereas in vitro transcription of the 7SK gene is severely reduced by a different TATA mutation (Murphy et al 1987a). Our results with the construction U6/dl -28, -13 (Fig.…”

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confidence: 99%

Upstream elements required for efficient transcription of a human U6 RNA gene resemble those of U1 and U2 genes even though a different polymerase is used.

Kunkel¹,

Pederson²

1988

Genes Dev.

154

142

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U6 small nuclear RNA is transcribed by a different polymerase than U1-U5 RNAs, likely to be RNA polymerase III. Transcription from human U6 gene deletion-substitution templates in a HeLa S100 extract delineated the 5' border of a control element lying between 67 and 43 bp upstream from the initiation site. This region matches the location of, and shows considerable sequence similarity with, the proximal control element of U1 and U2 RNA genes, which are transcribed by RNA polymerase II. Transfection of human 293 cells with 5'-flanking deletion-substitution mutants of a U6 maxigene revealed a dominant control element between 245 and 149 bp upstream of the transcription start site. An octamer motif was found in this region in an inverted orientation relative to that of the human U1 and U2 RNA gene enhancers but in the same orientation as a human U4 RNA gene, the transcript of which functions together with U6 RNA in a single small nuclear ribonucleoprotein (snRNP) particle. The human U2 gene enhancer joined to the U6 maxigene was able to functionally replace the U6 distal control element(s).

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The in vitro transcription of the 7SK RNA gene by RNA polymerase III is dependent only on the presence of an upstream promoter

Cited by 190 publications

References 19 publications

Deregulation of RNA polymerase III transcription in cervical epithelium in response to high-risk human papillomavirus

Deregulation of RNA polymerase III transcription in cervical epithelium in response to high-risk human papillomavirus

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

Upstream elements required for efficient transcription of a human U6 RNA gene resemble those of U1 and U2 genes even though a different polymerase is used.

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