Alleviation of PC4-mediated Transcriptional Repression by the ERCC3 Helicase Activity of General Transcription Factor TFIIH

Fukuda, Aya; Tokonabe, Shigeki; Hamada, Mitsuhiro; Matsumoto, Masahito; Tsukui, Tohru; Nogi, Yasuhisa; Hisatake, Koji

doi:10.1074/jbc.m213172200

Cited by 19 publications

(21 citation statements)

References 36 publications

(63 reference statements)

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“…A possible explanation combining all these results is that PC4 may function in TCR as an intermediary between RNA polymerase removal or remodeling by XPG together with other TCR proteins, possibly clearing the initial TCR machinery from the damaged region, and subsequent steps including recruitment of repair enzymes and synthesis of the repair patch. The observation that PC4 blocks RNA polymerase elongation in vitro and the ability of TFIIH to alleviate this block (17,57) raise the possibility that PC4 may also have additional functions in TCR that affect the resumption of transcription. Clearly, the close association of PC4 with other transcriptional processes and components of the transcription machinery makes a possible role for PC4 in transcription-coupled DNA repair processes particularly interesting.…”

Section: Discussionmentioning

confidence: 99%

The Single-Strand DNA Binding Activity of Human PC4 Prevents Mutagenesis and Killing by Oxidative DNA Damage

Wang

Sarker

Cooper

et al. 2004

Molecular and Cellular Biology

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Human positive cofactor 4 (PC4) is a transcriptional coactivator with a highly conserved single-strand DNA (ssDNA) binding domain of unknown function. We identified PC4 as a suppressor of the oxidative mutator phenotype of the Escherichia coli fpg mutY mutant and demonstrate that this suppression requires its ssDNA binding activity. Saccharomyces cerevisiae mutants lacking their PC4 ortholog Sub1 are sensitive to hydrogen peroxide and exhibit spontaneous and peroxide-induced hypermutability. PC4 expression suppresses the peroxide sensitivity of the yeast sub1⌬ mutant, suggesting that the human protein has a similar function. A role for yeast and human proteins in DNA repair is suggested by the demonstration that Sub1 acts in a peroxide resistance pathway involving Rad2 and by the physical interaction of PC4 with the human Rad2 homolog XPG. We show that XPG recruits PC4 to a bubble-containing DNA substrate with a resulting displacement of XPG and formation of a PC4-DNA complex. We discuss the possible requirement for PC4 in either global or transcription-coupled repair of oxidative DNA damage to mediate the release of XPG bound to its substrate.Oxidative DNA damage and the mutations it causes have been implicated in a number of human diseases, including cancer and neurodegenerative diseases, and are a contributing factor to aging (6,12,35,36). Thus, a thorough understanding of genes involved in the prevention and repair of oxidative DNA damage and its mutagenic consequences is important to our understanding of the mechanisms mitigating these diseases and exacerbating normal degenerative processes associated with aging.Oxidative DNA damage results from the interaction of reactive oxygen species (ROS) with DNA. ROS are produced as by-products of normal aerobic metabolism and by exogenous factors, such as ionizing radiation and chemical oxidants (6,12,35,36). The deleterious consequences of ROS to an organism's genetic material are held in check by proteins that prevent or repair oxidative DNA damage (7,12,13,15,21). Unrepaired oxidative lesions result in increased mutagenesis, lethality, and apoptosis (23,27). A balance between DNA repair and damage prevention mechanisms and ROS production is required to maintain a low spontaneous mutation rate. Factors that increase ROS production, reduce ROS detoxification, or factors that affect repair of oxidative DNA lesions result in increased mutagenesis. This is best demonstrated in Escherichia coli; mutations that inactivate the fpg and mutY genes, whose products repair the predominant oxidative lesion 8-oxoguanine (8-oxoG) and its mispaired intermediate 8-oxoG:A, respectively, result in a mutator phenotype that specifically increases GC3 TA transversion mutagenesis (37).In this study, we screened a human cDNA library and describe the isolation and characterization of the human transcription positive cofactor 4 (PC4) gene as a suppressor of oxidative mutagenesis in the E. coli fpg mutY strain. We demonstrate that PC4 and its Saccharomyces cerevisiae ortholog SUB1 are requi...

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Section: Discussionmentioning

confidence: 99%

The Single-Strand DNA Binding Activity of Human PC4 Prevents Mutagenesis and Killing by Oxidative DNA Damage

Wang

Sarker

Cooper

et al. 2004

Molecular and Cellular Biology

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“…Purification of recombinant factors (TFIIA, TFIIB, TFIIE, TFIIF, TFIIH, and GAL4-VP16), epitope-tagged TFIID, and RNA polymerase II were performed as described previously (10,12). Recombinant PC4 was purified as described previously (11). For 390-and 20-nucleotide (nt) transcripts, in vitro transcription reaction mixtures (25 l) contained 50 ng of negatively supercoiled pG5HMC2AT or its derivative, 12 mM HEPES-KOH (pH 7.9), 6% glycerol, 60 mM KCl, 0.6 mM EDTA, 8 (10), and the derived pppApC was treated with calf intestinal phosphatase to form ApC before electrophoresis (29).…”

Section: Methodsmentioning

confidence: 99%

Transcriptional Coactivator PC4 Stimulates Promoter Escape and Facilitates Transcriptional Synergy by GAL4-VP16

Fukuda

Nakadai

Shimada

et al. 2004

Molecular and Cellular Biology

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Positive cofactor 4 (PC4) is a coactivator that strongly augments transcription by various activators, presumably by facilitating the assembly of the preinitiation complex (PIC). However, our previous observation of stimulation of promoter escape in GAL4-VP16-dependent transcription in the presence of PC4 suggested a possible role for PC4 in this step. Here, we performed quantitative analyses of the stimulatory effects of PC4 on initiation, promoter escape, and elongation in GAL4-VP16-dependent transcription and found that PC4 possesses the ability to stimulate promoter escape in response to GAL4-VP16 in addition to its previously demonstrated effect on PIC assembly. This stimulatory effect of PC4 on promoter escape required TFIIA and the TATA box binding protein-associated factor subunits of TFIID. Furthermore, PC4 displayed physical interactions with both TFIIH and GAL4-VP16 through its coactivator domain, and these interactions were regulated distinctly by PC4 phosphorylation. Finally, GAL4-VP16 and PC4 stimulated both initiation and promoter escape to similar extents on the promoters with three and five GAL4 sites; however, they stimulated promoter escape preferentially on the promoter with a single GAL4 site. These results provide insight into the mechanism by which PC4 permits multiply bound GAL4-VP16 to attain synergy to achieve robust transcriptional activation.Transcription of mRNA-coding genes involves RNA polymerase II and six general transcription factors (TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH) which comprise the basal transcription machinery that recognizes the core promoter elements and elicits the basal level of transcription (50). Activated transcription requires the binding of activators to the regulatory DNA sequences typically present upstream of the core promoter and their interactions with the general transcription machinery (32,49). Despite the well-documented direct interactions of activators with the general transcription factors and RNA polymerase II, activated transcription requires yet another group of transcription factors, termed mediators or coactivators, that confer on the general transcription machinery a markedly enhanced responsiveness to activators (2,18,20,36,41).A wide array of coactivators may be grouped into two broad categories according to the requirement of chromatin for their action in biochemical assays. The coactivators which function on the templates without chromatin include the TATA box binding protein-associated factors (TAFs) present in TFIID (58), positive cofactors (PCs) (PC1, PC2, PC3, and PC4) derived from the upstream factor stimulatory activity (USA) cofactor fraction (20), and metazoan multiprotein complexes that are structurally related to the yeast mediator (40) (TRAP/ SMCC, ARC, DRIP, NAT, murine mediator, human mediator, CRSP, and PC2) (36, 41). The coactivators which require chromatin templates for their functions include CBP/p300, PCAF and its related GCN5 proteins, and p160 family proteins that display histone acetyltransferase activities (4,...

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“…Interferon-mediated growth arrest via the induction of p21 is most likely to occur in DAOY, in which p21 protein levels rise by at least 20-fold. Induction of PC4 in SWB61 and SWB40 by IRF-1 or IFN-␣/␤ additionally limits promoter-driven transcription as well as nonspecific transcription, which is additionally enhanced by the nonexpression of TFIIH and the suppression of ERCC3 expression (50). Another pathway involving IRF-1 in DAOY could be mediated by the induction of IFN ␣ and ␤, which up-regulate synthesis of ISG15 and suppress proliferation (49, 50).…”

Section: Effect Of Methionine Stress On Interferon-regulated Pathwaysmentioning

confidence: 99%

Modulation of Gene Expression in Human Central Nervous System Tumors under Methionine Deprivation-induced Stress

Kokkinakis

Liu

Chada³

et al. 2004

Cancer Research

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Methionine deprivation imposes a metabolic stress, termed methionine stress, that inhibits mitosis and induces cell cycle arrest and apoptosis. The methionine-dependent central nervous system tumor cell lines DAOY (medulloblastoma), SWB61 (anaplastic oligodendroglioma), SWB40 (anaplastic astrocytoma), and SWB39 (glioblastoma multiforme) were compared with methionine-stress resistant SWB77 (glioblastoma multiforme). In the methionine stress-resistant SWB77, only 20% of the above genes were affected, and then only to a lesser extent. In addition, some of the changes observed in SWB77 were opposite to those seen in methionine-dependent tumors, including expression of p21, TRAIL-R2, and TIEG. Despite similarities, differences between methionine-dependent tumors were substantial, especially in regard to regulation of cytokine expression. Western blot analysis confirmed that methionine stress caused the following: (a) a marked increase of GADD45␣ and ␥ in the wt-p53 cell lines SWB61 and 40; (b) an increase in GADD34 and p21 protein in all of the methionine-dependent lines; and (c) the induction of MDA7 and phospho-p38 in DAOY and SWB39, consistent with marked transcriptional activation of the former under methionine stress. It was additionally shown that methionine stress downregulated the highly active phosphatidylinositol 3-kinase pathway by reducing AKT phosphorylation, especially in DAOY and SWB77, and also reduced the levels of retinoblastoma (Rb) and pRb (P-ser780, P-ser795, and P-ser807/811), resulting in a shift in favor of unphosphorylated species in all of the methionine-dependent lines. Immunohistochemical analysis showed marked inhibition of nuclear translocation of nuclear factor B under methionine stress in methionine-dependent lines. In this study we show for the first time that methionine stress mobilizes several defined cell cycle checkpoints and proapoptotic pathways while coordinately inhibiting prosurvival mechanisms in central nervous system tumors. It is clear that methionine stress-induced cytotoxicity is not restricted by the p53 mutational status.

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Alleviation of PC4-mediated Transcriptional Repression by the ERCC3 Helicase Activity of General Transcription Factor TFIIH

Cited by 19 publications

References 36 publications

The Single-Strand DNA Binding Activity of Human PC4 Prevents Mutagenesis and Killing by Oxidative DNA Damage

The Single-Strand DNA Binding Activity of Human PC4 Prevents Mutagenesis and Killing by Oxidative DNA Damage

Transcriptional Coactivator PC4 Stimulates Promoter Escape and Facilitates Transcriptional Synergy by GAL4-VP16

Modulation of Gene Expression in Human Central Nervous System Tumors under Methionine Deprivation-induced Stress

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