Transcription factor GATA4 drives RNA polymerase III-directed transcription and transformed cell proliferation through a filamin A/GATA4/SP1 pathway

Specificity protein 1 (Sp1) is an important transcription factor implicated in numerous cellular processes. However, whether Sp1 is involved in the regulation of RNA polymerase III (Pol III)-directed gene transcription in human cells remains unknown. Here, we first show that filamin A (FLNA) represses Sp1 expression as well as expression of TFIIB-related factor 1 (BRF1) and general transcription factor III C subunit 2 (GTF3C2) in HeLa, 293T, and SaOS2 cell lines stably expressing FLNA-silencing shRNAs. Both BRF1 promoter 4 (BRF1P4) and GTF3C2 promoter 2 (GTF3C2P2) contain putative Sp1-binding sites, suggesting that Sp1 affects Pol III gene transcription by regulating BRF1 and GTF3C2 expression. We demonstrate that Sp1 knockdown inhibits Pol III gene transcription, BRF1 and GTF3C2 expression, and the proliferation of 293T and HeLa cells, whereas Sp1 overexpression enhances these activities. We obtained a comparable result in a cell line in which both FLNA and Sp1 were depleted. These results indicate that Sp1 is involved in the regulation of Pol III gene transcription independently of FLNA expression. Reporter gene assays showed that alteration of Sp1 expression affects BRF1P4 and GTF3C2P2 activation, suggesting that Sp1 modulates Pol III–mediated gene transcription by controlling BRF1 and GTF3C2 gene expression. Further analysis revealed that Sp1 interacts with and thereby promotes the occupancies of TATA box–binding protein, TFIIAα, and p300 at both BRF1P4 and GTF3C2P2. These findings indicate that Sp1 controls Pol III–directed transcription and shed light on how Sp1 regulates cancer cell proliferation.

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Effects of tRNATyr point mutations on the binding of yeast RNA polymerase III transcription factor C.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)57210-6 ◽

1986 ◽

Vol 261 (12) ◽

pp. 5275-5282

Author(s):

R E Baker ◽

O Gabrielsen ◽

B D Hall

Keyword(s):

Transcription Factor ◽

Rna Polymerase ◽

Rna Polymerase Iii ◽

Point Mutations ◽

Polymerase Iii ◽

Factor C

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Involvement of RNA Polymerase III in Immune Responses

Molecular and Cellular Biology ◽

10.1128/mcb.00990-14 ◽

2015 ◽

Vol 35 (10) ◽

pp. 1848-1859 ◽

Cited By ~ 17

Author(s):

Damian Graczyk ◽

Robert J. White ◽

Kevin M. Ryan

Keyword(s):

Transcription Factor ◽

Immune Responses ◽

Rna Polymerase ◽

Rna Polymerase Iii ◽

Trna Genes ◽

Malignant Cells ◽

Polymerase Iii ◽

Mouse Macrophages ◽

Tightly Coupled ◽

Pol Iii

Inflammation in the tumor microenvironment has many tumor-promoting effects. In particular, tumor-associated macrophages (TAMs) produce many cytokines which can support tumor growth by promoting survival of malignant cells, angiogenesis, and metastasis. Enhanced cytokine production by TAMs is tightly coupled with protein synthesis. In turn, translation of proteins depends on tRNAs, short abundant transcripts that are made by RNA polymerase III (Pol III). Here, we connect these facts by showing that stimulation of mouse macrophages with lipopolysaccharides (LPS) from the bacterial cell wall causes transcriptional upregulation of tRNA genes. The transcription factor NF-κB is a key transcription factor mediating inflammatory signals, and we report that LPS treatment causes an increased association of the NF-κB subunit p65 with tRNA genes. In addition, we show that p65 can directly associate with the Pol III transcription factor TFIIIB and that overexpression of p65 induces Pol III-dependent transcription. As a consequence of these effects, we show that inhibition of Pol III activity in macrophages restrains cytokine secretion and suppresses phagocytosis, two key functional characteristics of these cells. These findings therefore identify a radical new function for Pol III in the regulation of macrophage function which may be important for the immune responses associated with both normal and malignant cells.

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Interaction between a complex of RNA polymerase III subunits and the 70-kDa component of transcription factor IIIB.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)36839-5 ◽

1993 ◽

Vol 268 (28) ◽

pp. 20721-20724

Author(s):

M Werner ◽

N Chaussivert ◽

I.M. Willis ◽

A Sentenac

Keyword(s):

Transcription Factor ◽

Rna Polymerase ◽

Rna Polymerase Iii ◽

Polymerase Iii ◽

Transcription Factor Iiib

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Role of RNA Polymerase III Transcription Factors in the Selection of Integration Sites by the Dictyostelium Non-Long Terminal Repeat Retrotransposon TRE5-A

Molecular and Cellular Biology ◽

10.1128/mcb.01348-06 ◽

2006 ◽

Vol 26 (22) ◽

pp. 8242-8251 ◽

Cited By ~ 13

Author(s):

Oliver Siol ◽

Moustapha Boutliliss ◽

Thanh Chung ◽

Gernot Glöckner ◽

Theodor Dingermann ◽

...

Keyword(s):

Transcription Factor ◽

Rna Polymerase ◽

Long Terminal Repeat ◽

Integration Site ◽

Rna Polymerase Iii ◽

Terminal Repeat ◽

Trna Genes ◽

Ltr Retrotransposons ◽

Polymerase Iii

ABSTRACT In the compact Dictyostelium discoideum genome, non-long terminal repeat (non-LTR) retrotransposons known as TREs avoid accidental integration-mediated gene disruption by targeting the vicinity of tRNA genes. In this study we provide the first evidence that proteins of a non-LTR retrotransposon interact with a target-specific transcription factor to direct its integration. We applied an in vivo selection system that allows for the isolation of natural TRE5-A integrations into a known genomic location upstream of tRNA genes. TRE5-A frequently modified the integration site in a way characteristic of other non-LTR retrotransposons by adding nontemplated extra nucleotides and generating small and extended target site deletions. Mutations within the B-box promoter of the targeted tRNA genes interfered with both the in vitro binding of RNA polymerase III transcription factor TFIIIC and the ability of TRE5-A to target these genes. An isolated B box was sufficient to enhance TRE5-A integration in the absence of a surrounding tRNA gene. The RNA polymerase III-transcribed ribosomal 5S gene recruits TFIIIC in a B-box-independent manner, yet it was readily targeted by TRE5-A in our assay. These results suggest a direct role of an RNA polymerase III transcription factor in the targeting process.

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Transcription-independent TFIIIC-bound sites cluster near heterochromatin boundaries within lamina-associated domains in C. elegans

Epigenetics & Chromatin ◽

10.1186/s13072-019-0325-2 ◽

2020 ◽

Vol 13 (1) ◽

Cited By ~ 1

Author(s):

Alexis V. Stutzman ◽

April S. Liang ◽

Vera Beilinson ◽

Kohta Ikegami

Keyword(s):

Transcription Factor ◽

Rna Polymerase ◽

Mammalian Cells ◽

Sex Chromosome ◽

Rna Polymerase Iii ◽

Chromatin Organization ◽

Control Of Gene Expression ◽

C Elegans ◽

Polymerase Iii ◽

The Individual

Abstract Background Chromatin organization is central to precise control of gene expression. In various eukaryotic species, domains of pervasive cis-chromatin interactions demarcate functional domains of the genomes. In nematode Caenorhabditis elegans, however, pervasive chromatin contact domains are limited to the dosage-compensated sex chromosome, leaving the principle of C. elegans chromatin organization unclear. Transcription factor III C (TFIIIC) is a basal transcription factor complex for RNA polymerase III, and is implicated in chromatin organization. TFIIIC binding without RNA polymerase III co-occupancy, referred to as extra-TFIIIC binding, has been implicated in insulating active and inactive chromatin domains in yeasts, flies, and mammalian cells. Whether extra-TFIIIC sites are present and contribute to chromatin organization in C. elegans remains unknown. Results We identified 504 TFIIIC-bound sites absent of RNA polymerase III and TATA-binding protein co-occupancy characteristic of extra-TFIIIC sites in C. elegans embryos. Extra-TFIIIC sites constituted half of all identified TFIIIC binding sites in the genome. Extra-TFIIIC sites formed dense clusters in cis. The clusters of extra-TFIIIC sites were highly over-represented within the distal arm domains of the autosomes that presented a high level of heterochromatin-associated histone H3K9 trimethylation (H3K9me3). Furthermore, extra-TFIIIC clusters were embedded in the lamina-associated domains. Despite the heterochromatin environment of extra-TFIIIC sites, the individual clusters of extra-TFIIIC sites were devoid of and resided near the individual H3K9me3-marked regions. Conclusion Clusters of extra-TFIIIC sites were pervasive in the arm domains of C. elegans autosomes, near the outer boundaries of H3K9me3-marked regions. Given the reported activity of extra-TFIIIC sites in heterochromatin insulation in yeasts, our observation raised the possibility that TFIIIC may also demarcate heterochromatin in C. elegans.

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