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Nunlist EH, Dozmorov I, Tang Y, Cowan R, Centola M, Lin HK. Partitioning of 5alpha-dihydrotestosterone and 5alpha-androstane-3alpha, 17beta-diol activated pathways for stimulating human prostate cancer LNCaP cell proliferation. J Steroid Biochem Mol Biol 2004; 91:157-70. [PMID: 15276623 DOI: 10.1016/j.jsbmb.2004.02.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 02/24/2004] [Indexed: 11/24/2022]
Abstract
The growth and development of the prostate gland are regulated by androgens. Despite our understanding of molecular actions of 5alpha-dihydrotestosterone (5alpha-DHT) in the prostate through the trans-activation of the androgen receptor (AR), comprehensive analysis of androgen responsive genes (ARGs) has just been started. Moreover, expression changes induced by the androgen effects of 5alpha-androstane-3alpha,17beta-diol (3alpha-diol), a metabolite of 5alpha-DHT through the action of 3alpha-hydroxysteroid dehydrogenases (3alpha-HSDs), remain undefined. We demonstrated that both 5alpha-DHT and 3alpha-diol stimulated similar levels of androgen sensitive human prostate cancer LNCaP cell proliferation. However, consistent with the fact that 3alpha-diol has low affinity toward the AR, 3alpha-diol did not elicit the same levels of AR trans-activation activity as that of 5alpha-DHT. Since LNCaP cells respond to androgen stimulation by transcriptionally activating the AR downstream genes, gene expression patterns between 0 and 48 h following 3alpha-diol and 5alpha-DHT stimulation were analyzed using cDNA-based membrane arrays to define the temporal regulation of ARGs. Array analysis identified 217 and 219 androgen-modulated genes in at least one time point following 3alpha-diol and 5alpha-DHTstimulation, respectively, including key regulators of cell proliferation. Only a subset of these genes (143) was regulated by both androgens. These data suggest that 3alpha-diol exerts androgenic effects independent of the action of 5alpha-DHT in steroid target tissues. Accordingly, 3alpha-diol might activate cell proliferation cascades independent of AR pathway in the prostate.
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Affiliation(s)
- Eva H Nunlist
- Department of Urology, University of Oklahoma Health Sciences Center, 920 Stanton L. Young Blvd., WP3150, Oklahoma City, OK 73104, USA
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52
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Abstract
Cell cycle is one of the most complex processes in the life of a dividing cell. It involves numerous regulatory proteins, which direct the cell through a specific sequence of events for the production of two daughter cells. Cyclin-dependent kinases (cdks), which complex with the cyclin proteins, are the main players in the cell cycle. They can regulate the progression of the cells through different stages regulated by several proteins including p53, p21(WAF1), p19, p16, and cdc25. Downstream targets of cyclin-cdk complexes include pRB and E2F. A cell cycle can be altered to the advantage of many viral agents, most notably polyomaviruses, papillomaviruses, adenoviruses, and retroviruses. In addition, viral protein R (Vpr) is a protein encoded by the human immunodeficiency virus type 1 (HIV-1). HIV-1, the causative agent of acquired immunodeficiency syndrome (AIDS), is a member of the lentivirus class of retroviruses. This accessory protein plays an important role in the regulation of the cell cycle by causing G(2) arrest and affecting cell cycle regulators. Vpr prevents infected cells from proliferating, and collaborates with the matrix protein (MA) to enable HIV-1 to enter the nucleus of nondividing cells. Studies from different labs including ours showed that Vpr affects the functions of cell cycle proteins, including p53 and p21(WAF1). Thus, the replication of HIV-1, and ultimately its pathogenesis, are intrinsically tied to cell-cycle control.
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Affiliation(s)
- Shohreh Amini
- Center for Neurovirology and Cancer Biology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA
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53
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Le May N, Dubaele S, Proietti De Santis L, Billecocq A, Bouloy M, Egly JM. TFIIH Transcription Factor, a Target for the Rift Valley Hemorrhagic Fever Virus. Cell 2004; 116:541-50. [PMID: 14980221 DOI: 10.1016/s0092-8674(04)00132-1] [Citation(s) in RCA: 235] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2003] [Revised: 01/06/2004] [Accepted: 01/09/2004] [Indexed: 11/30/2022]
Abstract
The Rift Valley fever virus (RVFV) is the causative agent of fatal hemorrhagic fever in humans and acute hepatitis in ruminants. We found that infection by RVFV leads to a rapid and drastic suppression of host cellular RNA synthesis that parallels a decrease of the TFIIH transcription factor cellular concentration. Using yeast two hybrid system, recombinant technology, and confocal microscopy, we further demonstrated that the nonstructural viral NSs protein interacts with the p44 component of TFIIH to form nuclear filamentous structures that also contain XPB subunit of TFIIH. By competing with XPD, the natural partner of p44 within TFIIH, and sequestering p44 and XPB subunits, NSs prevents the assembly of TFIIH subunits, thus destabilizing the normal host cell life. These observations shed light on the mechanism utilized by RVFV to evade the host response.
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Affiliation(s)
- Nicolas Le May
- Unité de Génétique Moléculaire des Bunyaviridés, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris, Cedex 15, France
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54
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Ohkawa K, Ishida H, Nakanishi F, Hosui A, Ueda K, Takehara T, Hori M, Hayashi N. Hepatitis C virus core functions as a suppressor of cyclin-dependent kinase-activating kinase and impairs cell cycle progression. J Biol Chem 2004; 279:11719-26. [PMID: 14711830 DOI: 10.1074/jbc.m308560200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We investigated how the hepatitis C virus (HCV) core protein affects the cell cycle profile and cell cycle-related molecules by using the HCV core-expressing stable transfectant. Analysis of the cell cycle profile showed that HCV core impaired G(1) to S transition. The E2F-mediated transcription, phosphorylation of the retinoblastoma protein, and cyclin-dependent kinase (CDK) 4 and CDK2 activities were suppressed in HCV core-expressing cells. The expression levels of G(1) phase-related CDKs/cyclins and various CDK inhibitors were not substantially affected by expression of HCV core. When influences of HCV core on CDK-activating kinase (CAK) were examined, the expression levels of the CAK components, CDK7, cyclin H, and MAT1, were not affected. However, formation of the ternary CAK complex, CAK activity, and the CDK2 level with activating phosphorylation were inhibited by expression of the HCV core. The direct effect of HCV core on CAK was further assessed in the cell-free system by adding the in vitro translated HCV core protein to the anti-CDK7 immunoprecipitate from the cell. The results showed that HCV core led to dissociation of MAT1 from the CAK complex and suppressed the CAK activity. Furthermore, the binding assay revealed that the HCV core was directed against CDK7. Their interaction occurred mainly in the nucleus by the immunostaining. In conclusion, the HCV core protein interacts with CAK and functions as an extrinsic suppressor of CAK. This may be the molecular basis of HCV core-mediated suppression of cell cycle progression. Our findings suggest a novel mechanism concerning HCV core-mediated alteration in the cell cycle machinery.
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Affiliation(s)
- Kazuyoshi Ohkawa
- Department of Molecular Therapeutics, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
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55
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Wang J, Barsky LW, Shum CH, Jong A, Weinberg KI, Collins SJ, Triche TJ, Wu L. Retinoid-induced G1 arrest and differentiation activation are associated with a switch to cyclin-dependent kinase-activating kinase hypophosphorylation of retinoic acid receptor alpha. J Biol Chem 2002; 277:43369-76. [PMID: 12213824 DOI: 10.1074/jbc.m206792200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cell cycle G(1) exit is a critical stage where cells commonly commit to proliferate or to differentiate, but the biochemical events that regulate the proliferation/differentiation (P/D) transition at G(1) exit are presently unclear. We previously showed that MAT1 (ménage à trois 1), an assembly factor and targeting subunit of the cyclin-dependent kinase (CDK)-activating kinase (CAK), modulates CAK activities to regulate G(1) exit. Here we find that the retinoid-induced G(1) arrest and differentiation activation of cultured human leukemic cells are associated with a switch to CAK hypophosphorylation of retinoic acid receptor alpha (RARalpha) from CAK hyperphosphorylation of RARalpha. The switch to CAK hypophosphorylation of RARalpha is accompanied by decreased MAT1 expression and MAT1 fragmentation that occurs in the differentiating cells through the all-trans-retinoic acid (ATRA)-mediated proteasome degradation pathway. Because HL60R cells that harbor a truncated ligand-dependent AF-2 domain of RARalpha do not demonstrate any changes in MAT1 levels or CAK phosphorylation of RARalpha following ATRA stimuli, these biochemical changes appear to be mediated directly through RARalpha. These studies indicate that significant changes in MAT1 levels and CAK activities on RARalpha phosphorylation accompany the ATRA-induced G(1) arrest and differentiation activation, which provide new insights to explore the inversely coordinated P/D transition at G(1) exit.
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Affiliation(s)
- Jiwei Wang
- Department of Pathology, Division of Research Immunology/Bone Marrow Transplant, Childrens Hospital Los Angeles Research Institute, Los Angeles, California 90027, USA
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56
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Kino T, Tsukamoto M, Chrousos G. Transcription factor TFIIH components enhance the GR coactivator activity but not the cell cycle-arresting activity of the human immunodeficiency virus type-1 protein Vpr. Biochem Biophys Res Commun 2002; 298:17-23. [PMID: 12379213 DOI: 10.1016/s0006-291x(02)02442-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The human immunodeficiency virus type-1 (HIV-1)-accessory protein Vpr interacts with and potentiates the activity of the glucocorticoid receptor (GR) and arrests the host cell cycle at the G2/M boundary. Here we report that three core components of the general transcription factor (TF) IIH, CDK7, Cyclin H, and MAT1, enhance Vpr's GR coactivator activity but inhibit its cell cycle-arresting function. A CDK7 mutant defective in kinase activity for the C-terminal tail of RNA polymerase II, which cannot form a functional TFIIH complex, did not enhance Vpr coactivator activity. Overexpression of all three TFIIH components and p300 cooperatively enhanced Vpr coactivator activity, whereas TFIIH overexpression did not potentiate the transcriptional activity of a Vpr mutant, which does not bind p300/CBP. These findings suggest that TFIIH participates in Vpr's GR coactivating activity, at a step beyond its interaction with p300/CBP.
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Affiliation(s)
- Tomoshige Kino
- Pediatric and Reproductive Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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57
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Faust M, Kartarius S, Schwindling SL, Montenarh M. Cyclin H is a new binding partner for protein kinase CK2. Biochem Biophys Res Commun 2002; 296:13-9. [PMID: 12147220 DOI: 10.1016/s0006-291x(02)00825-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The protein kinase CK2 holoenzyme is composed of two regulatory beta- and two catalytic alpha- or alpha(')-subunits. There is ample evidence for the binding of individual subunits of CK2 to various cellular proteins and, moreover, for functions of the individual subunits, which are different from their roles in the holoenzyme. Here, we report that the regulatory cyclin H subunit of the cyclin H/cdk7/Mat1 complex was associated with a protein kinase activity, which shows some similarity with protein kinase CK2. Coimmunoprecipitation experiments supported the existence of complexes of cyclin H and CK2 in mammalian cells. Far Western blot experiments revealed that cyclin H bound to the alpha-subunit but not the alpha(')- and beta-subunits of CK2. Immunofluorescence analysis showed that cyclin H and CK2alpha were colocated in the nucleus. Although cyclin H functions as the regulatory subunit for the cyclin H/cdk7/Mat1 complex, it could not substitute the regulatory beta-subunit of CK2 in its regulatory function of the CK2 activity.
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Affiliation(s)
- Michael Faust
- Medical Biochemistry and Molecular Biology, University of the Saarland, Building 44, D-66424, Homburg/Saar, Germany
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58
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Keriel A, Stary A, Sarasin A, Rochette-Egly C, Egly JM. XPD mutations prevent TFIIH-dependent transactivation by nuclear receptors and phosphorylation of RARalpha. Cell 2002; 109:125-35. [PMID: 11955452 DOI: 10.1016/s0092-8674(02)00692-x] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inherited mutations in the XPD subunit of the general transcription/repair factor TFIIH yield the rare genetic disorder Xeroderma pigmentosum (XP), the phenotypes of which cannot be explained solely on the basis of a DNA repair defect. In cells derived from XP-D patients, we observed a reduction of the ligand-dependent transactivation mediated by several nuclear receptors (RARalpha, ERalpha, and AR). We demonstrate that the XPD mutation alters cdk7 function in RARalpha phosphorylation. Transactivation is restored upon overexpression of either the wild-type XPD or the RARalphaS77E (a mutation which mimics phosphorylated RARalpha). Thus, we demonstrate that the cdk7 kinase of TFIIH phosphorylates the nuclear receptor, then allowing ligand-dependent control of the activation of the hormone-responsive genes.
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Affiliation(s)
- Anne Keriel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP 163, 67404 Illkirch Cedex, C. U., Strasbourg, France
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59
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Keogh MC, Cho EJ, Podolny V, Buratowski S. Kin28 is found within TFIIH and a Kin28-Ccl1-Tfb3 trimer complex with differential sensitivities to T-loop phosphorylation. Mol Cell Biol 2002; 22:1288-97. [PMID: 11839796 PMCID: PMC134711 DOI: 10.1128/mcb.22.5.1288-1297.2002] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2001] [Revised: 11/14/2001] [Accepted: 11/30/2001] [Indexed: 11/20/2022] Open
Abstract
Basal transcription factor TFIIH phosphorylates the RNA polymerase II (RNApII) carboxy-terminal domain (CTD) within the transcription initiation complex. The catalytic kinase subunit of TFIIH is a member of the cyclin-dependent kinase (Cdk) family, designated Kin28 in Saccharomyces cerevisiae and Cdk7 in higher eukaryotes. Together with TFIIH subunits cyclin H and Mat1, Cdk7 kinase is also found in a trimer complex known as Cdk activating kinase (CAK). A yeast trimer complex has not previously been identified, although a Kin28-Ccl1 dimer called TFIIK has been isolated as a breakdown product of TFIIH. Here we show that a trimeric complex of Kin28-Ccl1-Tfb3 exists in yeast extracts. Several Kin28 point mutants that are defective in CTD phosphorylation were created. Consistent with earlier studies, these mutants have no transcriptional defect in vitro. Like other Cdks, Kin28 is activated by phosphorylation on T162 of the T loop. Kin28 T162 mutants have no growth defects alone but do demonstrate synthetic phenotypes when combined with mutant versions of the cyclin partner, Ccl1. Surprisingly, these phosphorylation site mutants appear to destabilize the association of the cyclin subunit within the context of TFIIH but not within the trimer complex.
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Affiliation(s)
- Michael-Christopher Keogh
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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60
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van Brabant AJ, Stan R, Ellis NA. DNA helicases, genomic instability, and human genetic disease. Annu Rev Genomics Hum Genet 2002; 1:409-59. [PMID: 11701636 DOI: 10.1146/annurev.genom.1.1.409] [Citation(s) in RCA: 203] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA helicases are a highly conserved group of enzymes that unwind DNA. They function in all processes in which access to single-stranded DNA is required, including DNA replication, DNA repair and recombination, and transcription of RNA. Defects in helicases functioning in one or more of these processes can result in characteristic human genetic disorders in which genomic instability and predisposition to cancer are common features. So far, different helicase genes have been found mutated in six such disorders. Mutations in XPB and XPD can result in xeroderma pigmentosum, Cockayne syndrome, or trichothiodystrophy. Mutations in the RecQ-like genes BLM, WRN, and RECQL4 can result in Bloom syndrome, Werner syndrome, and Rothmund-Thomson syndrome, respectively. Because XPB and XPD function in both nucleotide excision repair and transcription initiation, the cellular phenotypes associated with a deficiency of each one of them include failure to repair mutagenic DNA lesions and defects in the recovery of RNA transcription after UV irradiation. The functions of the RecQ-like genes are unknown; however, a growing body of evidence points to a function in restarting DNA replication after the replication fork has become stalled. The genomic instability associated with mutations in the RecQ-like genes includes spontaneous chromosome instability and elevated mutation rates. Mouse models for nearly all of these entities have been developed, and these should help explain the widely different clinical features that are associated with helicase mutations.
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Affiliation(s)
- A J van Brabant
- Department of Human Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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61
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Oelgeschläger T. Regulation of RNA polymerase II activity by CTD phosphorylation and cell cycle control. J Cell Physiol 2002; 190:160-9. [PMID: 11807820 DOI: 10.1002/jcp.10058] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The carboxyl-terminal domain (CTD) of the largest subunit of mammalian RNA polymerase II (RNAP II) consists of 52 repeats of a consensus heptapeptide and is subject to phosphorylation and dephosphorylation events during each round of transcription. RNAP II activity is regulated during the cell cycle and cell cycle-dependend changes in RNAP II activity correlate well with CTD phosphorylation. In addition, global changes in the CTD phosphorylation status are observed in response to mitogenic or cytostatic signals such as growth factors, mitogens and DNA-damaging agents. Several CTD kinases are members of the cyclin-dependent kinase (CDK) superfamily and associate with transcription initiation complexes. Other CTD kinases implicated in cell cycle regulation include the mitogen-activated protein kinases ERK-1/2 and the c-Abl tyrosine kinase. These observations suggest that reversible RNAP II CTD phosphorylation may play a key role in linking cell cycle regulatory events to coordinated changes in transcription.
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Affiliation(s)
- Thomas Oelgeschläger
- Eukaryotic Gene Regulation Laboratory, Marie Curie Research Institute, The Chart, Oxted, Surrey, United Kingdom.
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62
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Sandrock B, Egly JM. A yeast four-hybrid system identifies Cdk-activating kinase as a regulator of the XPD helicase, a subunit of transcription factor IIH. J Biol Chem 2001; 276:35328-33. [PMID: 11445587 DOI: 10.1074/jbc.m105570200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To understand the role of the various components of TFIIH, a DNA repair/transcription factor, a yeast four-hybrid system was designed. When the ternary Cdk-activating kinase (CAK) complex composed of Cdk7, cyclin H, and MAT1 was used as bait, the xeroderma pigmentosum (XP) D helicase of transcription factor IIH (TFIIH), among other proteins, was identified as an interacting partner. Deletion mutant analyses demonstrated that the coiled-coil and the hydrophobic domains of MAT1 interlink the CAK complex directly with the N-terminal domain of XPD. Using immunoprecipitates from cells coinfected with baculoviruses, we further validated the bridging function of XPD, which anchors CAK to the core TFIIH. In addition we show that upon interaction with MAT1, CAK inhibits the helicase activity of XPD. This inhibition is overcome upon binding to p44, a subunit of the core TFIIH. It is not surprising that under these conditions some XPD mutations affect interactions not only with p44, but also with MAT1, thus preventing either the CAK inhibitory function within CAK.XPD and/or the role of CAK within TFIIH and, consequently, explaining the variety of the XP phenotypes.
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Affiliation(s)
- B Sandrock
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur, B. P. 163, 67404 Illkirch Cedex, France
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63
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Fuchs M, Gerber J, Drapkin R, Sif S, Ikura T, Ogryzko V, Lane WS, Nakatani Y, Livingston DM. The p400 complex is an essential E1A transformation target. Cell 2001; 106:297-307. [PMID: 11509179 DOI: 10.1016/s0092-8674(01)00450-0] [Citation(s) in RCA: 235] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Here, we report the identification of a new E1A binding protein complex that is essential for E1A-mediated transformation. Its core component is a SWI2/SNF2-related, 400 kDa protein (p400). Other components include the myc- and p/CAF-associated cofactor, TRRAP/PAF400, the DNA helicases TAP54alpha/beta, actin-like proteins, and the human homolog of the Drosophila Enhancer of Polycomb protein. An E1A mutant, defective in p400 binding, is also defective in transformation. Certain p400 fragments partially rescued this phenotype, underscoring the role of E1A-p400 complex formation in the E1A transforming process. Furthermore, E1A and c-myc each alter the subunit composition of p400 complexes, implying that physiological p400 complex formation contributes to transformation suppression.
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Affiliation(s)
- M Fuchs
- Dana-Farber Cancer Institute, Boston, MA, USA
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64
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Fukuda A, Yamauchi J, Wu SY, Chiang CM, Muramatsu M, Hisatake K. Reconstitution of recombinant TFIIH that can mediate activator-dependent transcription. Genes Cells 2001; 6:707-19. [PMID: 11532030 DOI: 10.1046/j.1365-2443.2001.00456.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND TFIIH is one of the general transcription factors required for accurate transcription of protein-coding genes by RNA polymerase II. TFIIH has helicase and kinase activities, plays a role in promoter opening and promoter escape, and is also implicated in efficient activator-dependent transcription. RESULTS We have established a reconstitution system of recombinant TFIIH using a three-virus baculovirus expression system. The recombinant TFIIH was active in CTD kinase and DNA helicase assays, and showed both basal and activator-dependent transcriptional activities that were indistinguishable from those of HeLa cell-derived TFIIH. Further analyses using recombinant TFIIH confirmed a critical role of TFIIH in activator-dependent transcription. The dose response of TFIIH in activator-dependent transcription suggested that mere recruitment of TFIIH is not sufficient for transcriptional activation. The sensitivity of activator-dependent transcription to nonhydrolysable ATP analogues indicated the importance of the enzymatic activities of TFIIH in transcriptional activation. CONCLUSIONS Our results raise a possibility that transcriptional activation by GAL4-VP16 requires enzymatic activities. Recombinant TFIIH reconstituted from this baculovirus system should be useful for analysis of the mechanisms of activation by GAL4-VP16.
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Affiliation(s)
- A Fukuda
- Department of Biochemistry, Saitama Medical School, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
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65
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Larochelle S, Chen J, Knights R, Pandur J, Morcillo P, Erdjument-Bromage H, Tempst P, Suter B, Fisher RP. T-loop phosphorylation stabilizes the CDK7-cyclin H-MAT1 complex in vivo and regulates its CTD kinase activity. EMBO J 2001; 20:3749-59. [PMID: 11447116 PMCID: PMC125544 DOI: 10.1093/emboj/20.14.3749] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cyclin-dependent kinase (CDK)7-cyclin H, the CDK-activating kinase (CAK) and TFIIH-associated kinase in metazoans can be activated in vitro through T-loop phosphorylation or binding to the RING finger protein MAT1. Although the two mechanisms can operate independently, we show that in a physiological setting, MAT1 binding and T-loop phosphorylation cooperate to stabilize the CAK complex of Drosophila. CDK7 forms a stable complex with cyclin H and MAT1 in vivo only when phosphorylated on either one of two residues (Ser164 or Thr170) in its T-loop. Mutation of both phosphorylation sites causes temperature-dependent dissociation of CDK7 complexes and lethality. Furthermore, phosphorylation of Thr170 greatly stimulates the activity of the CDK7- cyclin H-MAT1 complex towards the C-terminal domain of RNA polymerase II without significantly affecting activity towards CDK2. Remarkably, the substrate-specific increase in activity caused by T-loop phosphorylation is due entirely to accelerated enzyme turnover. Thus phosphorylation on Thr170 could provide a mechanism to augment CTD phosphorylation by TFIIH-associated CDK7, and thereby regulate transcription.
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Affiliation(s)
- Stéphane Larochelle
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Jian Chen
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Ronald Knights
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Judit Pandur
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Patrick Morcillo
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Hediye Erdjument-Bromage
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Paul Tempst
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Beat Suter
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
| | - Robert P. Fisher
- Cell Biology Program and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA and Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, PQ, Canada H3A 1B1 Corresponding author e-mail:
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66
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Kim JM, McGaughy JT, Bogle RK, Ravnik SE. Meiotic expression of the cyclin H/Cdk7 complex in male germ cells of the mouse. Biol Reprod 2001; 64:1400-8. [PMID: 11319144 DOI: 10.1095/biolreprod64.5.1400] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Cell division requires that cyclin-dependent kinases (Cdks) be activated by phosphorylation. In mitotic cells, this is accomplished by the Cdk-activating-kinase (CAK), which is a complex of cyclin H and Cdk7. There are currently no data on the role of CAK in meiotic cells. Previously, we have shown that cyclin A1 is meiosis-specific and forms an active kinase with Cdk2. Because cyclin A1 is required for meiosis, and its associated kinase must be phosphorylated (activated), we propose that cyclin H/Cdk7 function to activate cyclin A1/Cdk2 in meiotic cells. Here, we show that cyclin H and Cdk7 are present during meiosis. Using reverse transcription-polymerase chain reaction and in situ hybridization, we show that the mRNAs encoding cyclin H and Cdk7 are abundant in spermatocytes. Immunohistochemistry localized cyclin H and Cdk7 to the nucleus of spermatocytes in stages IV to XII of the spermatogenic cycle, overlapping the same stages that express cyclin A1-associated kinases. Finally, immunoprecipitation and histone H1-kinase assays of cyclin H and Cdk7 from testicular extracts show that these proteins interact to form an active kinase. We conclude that cyclin H/Cdk7 complexes are present and during meiosis, form active complexes in testicular cells and are strong candidates for the activating kinase for cyclin A1-associated kinase.
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Affiliation(s)
- J M Kim
- Department of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, USA
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67
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Araújo SJ, Nigg EA, Wood RD. Strong functional interactions of TFIIH with XPC and XPG in human DNA nucleotide excision repair, without a preassembled repairosome. Mol Cell Biol 2001; 21:2281-91. [PMID: 11259578 PMCID: PMC86862 DOI: 10.1128/mcb.21.7.2281-2291.2001] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In mammalian cells, the core factors involved in the damage recognition and incision steps of DNA nucleotide excision repair are XPA, TFIIH complex, XPC-HR23B, replication protein A (RPA), XPG, and ERCC1-XPF. Many interactions between these components have been detected, using different physical methods, in human cells and for the homologous factors in Saccharomyces cerevisiae. Several human nucleotide excision repair (NER) complexes, including a high-molecular-mass repairosome complex, have been proposed. However, there have been no measurements of activity of any mammalian NER protein complex isolated under native conditions. In order to assess relative strengths of interactions between NER factors, we captured TFIIH from cell extracts with an anti-cdk7 antibody, retaining TFIIH in active form attached to magnetic beads. Coimmunoprecipitation of other NER proteins was then monitored functionally in a reconstituted repair system with purified proteins. We found that all detectable TFIIH in gently prepared human cell extracts was present in the intact nine-subunit form. There was no evidence for a repair complex that contained all of the NER components. At low ionic strength TFIIH could associate with functional amounts of each NER factor except RPA. At physiological ionic strength, TFIIH associated with significant amounts of XPC-HR23B and XPG but not other repair factors. The strongest interaction was between TFIIH and XPC-HR23B, indicating a coupled role of these proteins in early steps of repair. A panel of antibodies was used to estimate that there are on the order of 10(5) molecules of each core NER factor per HeLa cell.
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Affiliation(s)
- S J Araújo
- Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, United Kingdom
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68
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Gervais V, Busso D, Wasielewski E, Poterszman A, Egly JM, Thierry JC, Kieffer B. Solution structure of the N-terminal domain of the human TFIIH MAT1 subunit: new insights into the RING finger family. J Biol Chem 2001; 276:7457-64. [PMID: 11056162 DOI: 10.1074/jbc.m007963200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human MAT1 protein belongs to the cyclin-dependent kinase-activating kinase complex, which is functionally associated to the transcription/DNA repair factor TFIIH. The N-terminal region of MAT1 consists of a C3HC4 RING finger, which contributes to optimal TFIIH transcriptional activities. We report here the solution structure of the human MAT1 RING finger domain (Met(1)-Asp(65)) as determined by (1)H NMR spectroscopy. The MAT1 RING finger domain presents the expected betaalphabetabeta topology with two interleaved zinc-binding sites conserved among the RING family. However, the presence of an additional helical segment in the N-terminal part of the domain and a conserved hydrophobic central beta strand are the defining features of this new structure and more generally of the MAT1 RING finger subfamily. Comparison of electrostatic surfaces of RING finger structures shows that the RING finger domain of MAT1 presents a remarkable positively charged surface. The functional implications of these MAT1 RING finger features are discussed.
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Affiliation(s)
- V Gervais
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis Pasteur, 67400 Illkirch-Cedex, France
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69
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Kadkhodayan S, Coin F, Salazar EP, George JW, Egly JM, Thompson LH. Codominance associated with overexpression of certain XPD mutations. Mutat Res 2001; 485:153-68. [PMID: 11182546 DOI: 10.1016/s0921-8777(00)00077-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mutations in the XPD gene are associated with three complex clinical phenotypes, namely xeroderma pigmentosum (XP), XP in combination with Cockayne syndrome (XP-CS), and trichothiodystrophy (TTD). XP is caused by a deficiency in nucleotide excision repair (NER) that results in a high risk of skin cancer. TTD is characterized by severe developmental and neurological defects, with hallmark features of brittle hair and scaly skin, and sometimes has defective NER. We used CHO cells as a system to study how specific mutations alter the dominant/recessive behavior of XPD protein. Previously we identified the T46I and R75W mutations in two highly UV-sensitive hamster cell lines that were reported to have paradoxically high levels of unscheduled DNA synthesis. Here we report that these mutants have greatly reduced XPD helicase activity and fully defective NER in a cell-extract excision assay. We conclude that the unscheduled DNA synthesis seen in these mutants is caused by abortive "repair" that does not contribute to cell survival. These mutations, as well as the K48R canonical helicase-domain mutation, each produced codominant negative phenotypes when overexpressed in wild-type CHO cells. The common XP-specific R683W mutation also behaved in a codominant manner when overexpressed, which is consistent with the idea that this mutation may affect primarily the enzymatic activity of the protein rather than impairing protein interactions, which may underlie TTD. A C-terminal mutation uniquely found in TTD (R722W) was overexpressed but not to levels sufficiently high to rigorously test for a codominant phenotype. Overexpression of mutant XPD alleles may provide a simple means of producing NER deficiency in other cell lines.
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Affiliation(s)
- S Kadkhodayan
- Biology and Biotechnology Research Program, L441, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, USA
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70
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Liu J, Akoulitchev S, Weber A, Ge H, Chuikov S, Libutti D, Wang XW, Conaway JW, Harris CC, Conaway RC, Reinberg D, Levens D. Defective interplay of activators and repressors with TFIH in xeroderma pigmentosum. Cell 2001; 104:353-63. [PMID: 11239393 DOI: 10.1016/s0092-8674(01)00223-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inherited mutations of the TFIIH helicase subunits xeroderma pigmentosum (XP) B or XPD yield overlapping DNA repair and transcription syndromes. The high risk of cancer in these patients is not fully explained by the repair defect. The transcription defect is subtle and has proven more difficult to evaluate. Here, XPB and XPD mutations are shown to block transcription activation by the FUSE Binding Protein (FBP), a regulator of c-myc expression, and repression by the FBP Interacting Repressor (FIR). Through TFIIH, FBP facilitates transcription until promoter escape, whereas after initiation, FIR uses TFIIH to delay promoter escape. Mutations in TFIIH that impair regulation by FBP and FIR affect proper regulation of c-myc expression and have implications in the development of malignancy.
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Affiliation(s)
- J Liu
- Gene Regulation Section, Laboratory of Pathology, National Cancer Institute, National Institute of Health, Bethesda, MD 20892, USA
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71
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Hermand D, Westerling T, Pihlak A, Thuret JY, Vallenius T, Tiainen M, Vandenhaute J, Cottarel G, Mann C, Mäkelä TP. Specificity of Cdk activation in vivo by the two Caks Mcs6 and Csk1 in fission yeast. EMBO J 2001; 20:82-90. [PMID: 11226158 PMCID: PMC140202 DOI: 10.1093/emboj/20.1.82] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Activating phosphorylation of cyclin-dependent kinases (Cdks) is mediated by at least two structurally distinct types of Cdk-activating kinases (Caks): the trimeric Cdk7-cyclin H-Mat1 complex in metazoans and the single-subunit Cak1 in budding yeast. Fission yeast has both Cak types: Mcs6 is a Cdk7 ortholog and Csk1 a single-subunit kinase. Both phosphorylate Cdks in vitro and rescue a thermosensitive budding yeast CAK1 strain. However, this apparent redundancy is not observed in fission yeast in vivo. We have identified mutants that exhibit phenotypes attributable to defects in either Mcs6-activating phosphorylation or in Cdc2-activating phosphorylation. Mcs6, human Cdk7 and budding yeast Cak1 were all active as Caks for Cdc2 when expressed in fission yeast. Although Csk1 could activate Mcs6, it was unable to activate Cdc2. Biochemical experiments supported these genetic results: budding yeast Cak1 could bind and phosphorylate Cdc2 from fission yeast lysates, whereas fission yeast Csk1 could not. These results indicate that Mcs6 is the direct activator of Cdc2, and Csk1 only activates Mcs6. This demonstrates in vivo specificity in Cdk activation by Caks.
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Affiliation(s)
- Damien Hermand
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Thomas Westerling
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Arno Pihlak
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Jean-Yves Thuret
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Tea Vallenius
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Marianne Tiainen
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Jean Vandenhaute
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Guillaume Cottarel
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Carl Mann
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
| | - Tomi P. Mäkelä
- Haartman Institute & Biocentrum Helsinki, University of Helsinki, 00014 Helsinki, HUCH Laboratory Diagnostics, 00029 HYKS, Finland, Laboratoire de Génétique Moléculaire (GEMO), University of Namur (FUNDP), 61 Rue de Bruxelles, 5000 Namur, Belgium, Service de Biochimie et Genetique Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France and Genome Therapeutics Corp., 100 Beaver Street, Waltham, MA 02154, USA Corresponding author e-mail: D.Hermand & T.Westerling and A.Pihlak & J.-Y.Thuret, respectively, contributed equally to this work
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72
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Wu L, Chen P, Shum CH, Chen C, Barsky LW, Weinberg KI, Jong A, Triche TJ. MAT1-modulated CAK activity regulates cell cycle G(1) exit. Mol Cell Biol 2001; 21:260-70. [PMID: 11113200 PMCID: PMC88799 DOI: 10.1128/mcb.21.1.260-270.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The cyclin-dependent kinase (CDK)-activating kinase (CAK) is involved in cell cycle control, transcription, and DNA repair (E. A. Nigg, Curr. Opin. Cell. Biol. 8:312-317, 1996). However, the mechanisms of how CAK is integrated into these signaling pathways remain unknown. We previously demonstrated that abrogation of MAT1 (ménage à trois 1), an assembly factor and targeting subunit of CAK, induces G(1) arrest (L. Wu, P. Chen, J. J. Hwang, L. W. Barsky, K. I. Weinberg, A. Jong, and V. A. Starnes, J. Biol. Chem. 274:5564-5572, 1999). This result led us to investigate how deregulation of CAK by MAT1 abrogation affects the cell cycle G(1) exit, a process that is regulated most closely by phosphorylation of retinoblastoma tumor suppressor protein (pRb). Using mammalian cellular models that undergo G(1) arrest evoked by antisense MAT1 abrogation, we found that deregulation of CAK inhibits pRb phosphorylation and cyclin E expression, CAK phosphorylation of pRb is MAT1 dose dependent but cyclin D1/CDK4 independent, and MAT1 interacts with pRb. These results suggest that CAK is involved in the regulation of cell cycle G(1) exit while MAT1-modulated CAK formation and CAK phosphorylation of pRb may determine the cell cycle specificity of CAK in G(1) progression.
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Affiliation(s)
- L Wu
- Department of Pathology, Childrens Hospital Los Angeles Research Institute, Los Angeles, California 90027, USA.
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73
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Lehmann AR. The xeroderma pigmentosum group D (XPD) gene: one gene, two functions, three diseases. Genes Dev 2001; 15:15-23. [PMID: 11156600 DOI: 10.1101/gad.859501] [Citation(s) in RCA: 272] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- A R Lehmann
- MRC Cell Mutation Unit, University of Sussex, Falmer, Brighton BN1 9RR, UK.
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74
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Ronen A, Glickman BW. Human DNA repair genes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2001; 37:241-283. [PMID: 11317342 DOI: 10.1002/em.1033] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
DNA repair systems are essential for the maintenance of genome integrity. Consequently, the disregulation of repair genes can be expected to be associated with significant, detrimental health effects, which can include an increased prevalence of birth defects, an enhancement of cancer risk, and an accelerated rate of aging. Although original insights into DNA repair and the genes responsible were largely derived from studies in bacteria and yeast, well over 125 genes directly involved in DNA repair have now been identified in humans, and their cDNA sequence established. These genes function in a diverse set of pathways that involve the recognition and removal of DNA lesions, tolerance to DNA damage, and protection from errors of incorporation made during DNA replication or DNA repair. Additional genes indirectly affect DNA repair, by regulating the cell cycle, ostensibly to provide an opportunity for repair or to direct the cell to apoptosis. For about 70 of the DNA repair genes listed in Table I, both the genomic DNA sequence and the cDNA sequence and chromosomal location have been elucidated. In 45 cases single-nucleotide polymorphisms have been identified and, in some cases, genetic variants have been associated with specific disorders. With the accelerating rate of gene discovery, the number of identified DNA repair genes and sequence variants is quickly rising. This report tabulates the current status of what is known about these genes. The report is limited to genes whose function is directly related to DNA repair.
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Affiliation(s)
- A Ronen
- Centre for Environmental Health, University of Victoria, Victoria, British Columbia, Canada.
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75
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Korsisaari N, Mäkelä TP. Interactions of Cdk7 and Kin28 with Hint/PKCI-1 and Hnt1 histidine triad proteins. J Biol Chem 2000; 275:34837-40. [PMID: 10958787 DOI: 10.1074/jbc.c000505200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinase 7 (Cdk7) forms a trimeric complex with cyclin H and Mat1 to form the mammalian Cdk-activating kinase, CAK, as well as a part of the basal transcription factor TFIIH, where Cdk7 phosphorylates the C-terminal domain (CTD) of the large subunit of RNA polymerase II. Here, we report a novel interaction between Cdk7 and a histidine triad (HIT) family protein, Hint/PKCI-1. This interaction was initially observed in a yeast two-hybrid study and subsequently verified by co-immunoprecipitation and subcellular localization studies, where overexpression of Cdk7 leads to partial relocalization of Hint to the nucleus. The physical association is independent of cyclin H binding or Cdk7 kinase activity and is conserved between the related Sacharomyces cerevisiae CTD kinase Kin28 and the HIT protein Hnt1. Furthermore, combination of a disruption of HNT1 and a KIN28 temperature-sensitive allele in S. cerevisiae led to highly elongated cell morphology and reduced colony formation, indicating a genetic interaction between KIN28 and HNT1. The physical and genetic interactions of Hint and Hnt1 with Cdk7 and Kin28 suggest a role for this class of histidine triad proteins in the regulation of Cdk7 and Kin28 functions.
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Affiliation(s)
- N Korsisaari
- Haartman Institute & Biocentrum Helsinki, P. O. Box 21, University of Helsinki, 00014 Helsinki, Finland
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76
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Abstract
TFIIH is a multiprotein complex required for both transcription and DNA repair. Single particles of human TFIIH were revealed by electron microscopy and image processing at a resolution of 3.8 nm. TFIIH is 16 x 12.5 x 7.5 nm in size and is organized into a ring-like structure from which a large protein domain protrudes out. A subcomplex assembled from five recombinant core subunits also forms a circular architecture that can be superimposed on the ring found in human TFIIH. Immunolabeling experiments localize several subunits: p44, within the ring structure, forms the base of the protruding protein density which includes the cdk7 kinase, cyclin H, and MAT1. Within the ring structure, p44 was flanked on either side by the XPB and XPD helicases. These observations provide us with a quartenary organizational model of TFIIH.
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Affiliation(s)
- P Schultz
- Institut de Génétique et de Biologie Moléclaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France.
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77
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Busso D, Keriel A, Sandrock B, Poterszman A, Gileadi O, Egly JM. Distinct regions of MAT1 regulate cdk7 kinase and TFIIH transcription activities. J Biol Chem 2000; 275:22815-23. [PMID: 10801852 DOI: 10.1074/jbc.m002578200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription/DNA repair factor TFIIH may be resolved into at least two subcomplexes: the core TFIIH and the cdk-activating kinase (CAK) complex. The CAK complex, which is also found free in the cell, is composed of cdk7, cyclin H, and MAT1. In the present work, we found that the C terminus of MAT1 binds to the cdk7 x cyclin H complex and activates the cdk7 kinase activity. The median portion of MAT1, which contains a coiled-coil motif, allows the binding of CAK to the TFIIH core through interactions with both XPD and XPB helicases. Furthermore, using recombinant TFIIH complexes, it is demonstrated that the N-terminal RING finger domain of MAT1 is crucial for transcription activation and participates to the phosphorylation of the C-terminal domain of the largest subunit of the RNA polymerase II.
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Affiliation(s)
- D Busso
- Institut de Genetique et de Biologie Moleculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur, Boíte Postale 163, 67404 Illkirch Cedex, Communauté Urbaine de Strasbourg, France
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78
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Bastien J, Adam-Stitah S, Riedl T, Egly JM, Chambon P, Rochette-Egly C. TFIIH interacts with the retinoic acid receptor gamma and phosphorylates its AF-1-activating domain through cdk7. J Biol Chem 2000; 275:21896-904. [PMID: 10748061 DOI: 10.1074/jbc.m001985200] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retinoic acid receptor gamma (RARgamma) is phosphorylated in COS-1 cells at two conserved serine residues located in the N-terminal region (serines 77 and 79 in RARgamma1 and serines 66 and 68 in RARgamma2) that contains the activation function AF-1. These serines are phosphorylated in vitro by cdk7, a cyclin-dependent kinase associated to cyclin H and MAT1 in the CAK complex (cdk7.cyclin H. MAT1), that is found either free or as a component of the transcription/DNA repair factor TFIIH. RARgamma is more efficiently phosphorylated by TFIIH than by CAK and interacts not only with cdk7 but also with several additional subunits of TFIIH. RARgamma phosphorylation and interaction with TFIIH occur in a ligand-independent manner. Our data demonstrate also that phosphorylation of the AF-1 function modulates RARgamma transcriptional activity in a response gene-dependent manner.
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Affiliation(s)
- J Bastien
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis Pasteur/Collège de France, BP 163, 67404 Illkirch Cedex, France
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79
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Watanabe Y, Fujimoto H, Watanabe T, Maekawa T, Masutani C, Hanaoka F, Ohkuma Y. Modulation of TFIIH-associated kinase activity by complex formation and its relationship with CTD phosphorylation of RNA polymerase II. Genes Cells 2000; 5:407-23. [PMID: 10886368 DOI: 10.1046/j.1365-2443.2000.00336.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The general transcription factor TFIIH plays important roles in initiation and the transition to elongation steps of transcription by RNA polymerase II (PolII). Both roles are dependent on the protein kinase, DNA-dependent ATPase and DNA helicase activities of TFIIH. However, how these enzyme activities of TFIIH contribute to transcription has remained elusive. TFIIH consists of nine subunits, and one of them, Cdk7, possesses kinase activity. Here the substrate specificities of TFIIH and two forms of the Cdk7-containing kinase complex are compared, and the relationship between transcription activity and the TFIIH-dependent phosphorylation of the carboxy terminal domain of the largest subunit of PolII (CTD) is studied. RESULTS We prepared TFIIH and two Cdk7-containing kinase complexes, Cdk7/Cyclin H and CAK (Cdk7/Cyclin H/MAT1). Consistent with previous reports, CAK strongly phosphorylated Cdk2, Cdk4, CTD and intact PolII. In contrast, Cdk7/Cyclin H, which lacks MAT1, did not phosphorylate these substrates, except for weak phosphorylation of Cdk2. The kinase activity of TFIIH displayed stronger substrate preference for Cdk4 than did CAK. In addition, TFIIH phosphorylation of PolII was stimulated by TFIIE both in solution and during preinitiation complex formation, whereas Cdk7/Cyclin H and CAK phosphorylation of PolII was not. In combination with other general transcription factors, TFIIH, but not Cdk7/CycH or CAK, promoted transcription on a linear DNA template. This transcription was well correlated with TFIIE stimulated TFIIH phosphorylation of serine at position 5 (Ser-5) within the heptapeptide repeat of the PolII CTD. CONCLUSION These results provide clues about the roles of CTD phosphorylation at Ser-5 in transcription.
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Affiliation(s)
- Y Watanabe
- Institute for Molecular and Cellular Biology and; The Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
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80
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Araki M, Masutani C, Maekawa T, Watanabe Y, Yamada A, Kusumoto R, Sakai D, Sugasawa K, Ohkuma Y, Hanaoka F. Reconstitution of damage DNA excision reaction from SV40 minichromosomes with purified nucleotide excision repair proteins. Mutat Res 2000; 459:147-60. [PMID: 10725665 DOI: 10.1016/s0921-8777(99)00067-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We previously constructed the cell-free nucleotide excision repair (NER) assay system with UV-irradiated SV40 minichromosomes to analyze the mechanism of NER reaction on chromatin DNA. Here we investigate the factor that acts especially on nucleosomal DNA during the damage excision reaction, and reconstitute the damage excision reaction on SV40 minichromosomes. NER-proficient HeLa whole cell extracts were fractionated, and the amounts of known NER factors involved in the column fractions were determined by immunoblot analyses. The column fractions were quantitatively and systematically replaced by highly purified NER factors. Finally, damage DNA excision reaction on SV40 minichromosomes was reconstituted with six highly purified NER factors, XPA, XPC-HR23B, XPF-ERCC1, XPG, RPA and TFIIH, as those essential for the reaction with naked DNA. Further analysis showed that the damages on chromosomal DNA were excised as the same efficiency as those on naked DNA for short incubation. At longer incubation time, however, the damage excision efficiency on nucleosomal DNA was decreased whereas naked DNA was still vigorously repaired. These observations suggest that although the six purified NER factors have a potential to eliminate the damage DNA from SV40 minichromosomes, the chromatin structure may still have some repressive effects on NER.
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Affiliation(s)
- M Araki
- Institute for Molecular and Cellular Biology (IMCB), Osaka University, 1-3 Yamada-oka, Suita, Japan
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81
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Araújo SJ, Tirode F, Coin F, Pospiech H, Syväoja JE, Stucki M, Hübscher U, Egly JM, Wood RD. Nucleotide excision repair of DNA with recombinant human proteins: definition of the minimal set of factors, active forms of TFIIH, and modulation by CAK. Genes Dev 2000. [PMID: 10673506 DOI: 10.1101/gad.14.3.349] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During human nucleotide excision repair, damage is recognized, two incisions are made flanking a DNA lesion, and residues are replaced by repair synthesis. A set of proteins required for repair of most lesions is RPA, XPA, TFIIH, XPC-hHR23B, XPG, and ERCC1-XPF, but additional components have not been excluded. The most complex and difficult to analyze factor is TFIIH, which has a 6-subunit core (XPB, XPD, p44, p34, p52, p62) and a 3-subunit kinase (CAK). TFIIH has roles both in basal transcription initiation and in DNA repair, and several inherited human disorders are associated with mutations in TFIIH subunits. To identify the forms of TFIIH that can function in repair, recombinant XPA, RPA, XPC-hHR23B, XPG, and ERCC1-XPF were combined with TFIIH fractions purified from HeLa cells. Repair activity coeluted with the peak of TFIIH and with transcription activity. TFIIH from cells with XPB or XPD mutations was defective in supporting repair, whereas TFIIH from spinal muscular atrophy cells with a deletion of one p44 gene was active. Recombinant TFIIH also functioned in repair, both a 6- and a 9-subunit form containing CAK. The CAK kinase inhibitor H-8 improved repair efficiency, indicating that CAK can negatively regulate NER by phosphorylation. The 15 recombinant polypeptides define the minimal set of proteins required for dual incision of DNA containing a cisplatin adduct. Complete repair was achieved by including highly purified human DNA polymerase delta or epsilon, PCNA, RFC, and DNA ligase I in reaction mixtures, reconstituting adduct repair for the first time with recombinant incision factors and human replication proteins.
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Affiliation(s)
- S J Araújo
- Imperial Cancer Research Fund (ICRF), Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, UK
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82
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Winkler GS, Araújo SJ, Fiedler U, Vermeulen W, Coin F, Egly JM, Hoeijmakers JH, Wood RD, Timmers HT, Weeda G. TFIIH with inactive XPD helicase functions in transcription initiation but is defective in DNA repair. J Biol Chem 2000; 275:4258-66. [PMID: 10660593 DOI: 10.1074/jbc.275.6.4258] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TFIIH is a multisubunit protein complex involved in RNA polymerase II transcription and nucleotide excision repair, which removes a wide variety of DNA lesions including UV-induced photoproducts. Mutations in the DNA-dependent ATPase/helicase subunits of TFIIH, XPB and XPD, are associated with three inherited syndromes as follows: xeroderma pigmentosum with or without Cockayne syndrome and trichothiodystrophy. By using epitope-tagged XPD we purified mammalian TFIIH carrying a wild type or an active-site mutant XPD subunit. Contrary to XPB, XPD helicase activity was dispensable for in vitro transcription, catalytic formation of trinucleotide transcripts, and promoter opening. Moreover, in contrast to XPB, microinjection of mutant XPD cDNA did not interfere with in vivo transcription. These data show directly that XPD activity is not required for transcription. However, during DNA repair, neither 5' nor 3' incisions in defined positions around a DNA adduct were detected in the presence of TFIIH containing inactive XPD, although substantial damage-dependent DNA synthesis was induced by the presence of mutant XPD both in cells and cell extracts. The aberrant damage-dependent DNA synthesis caused by the mutant XPD does not lead to effective repair, consistent with the discrepancy between repair synthesis and survival in cells from a number of XP-D patients.
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Affiliation(s)
- G S Winkler
- Department of Cell Biology and Genetics, Medical Genetics Center, Erasmus University Rotterdam, P. O. Box 1738, 3000 DR Rotterdam, The Netherlands
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83
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Araújo SJ, Tirode F, Coin F, Pospiech H, Syväoja JE, Stucki M, Hübscher U, Egly JM, Wood RD. Nucleotide excision repair of DNA with recombinant human proteins: definition of the minimal set of factors, active forms of TFIIH, and modulation by CAK. Genes Dev 2000; 14:349-59. [PMID: 10673506 PMCID: PMC316364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
During human nucleotide excision repair, damage is recognized, two incisions are made flanking a DNA lesion, and residues are replaced by repair synthesis. A set of proteins required for repair of most lesions is RPA, XPA, TFIIH, XPC-hHR23B, XPG, and ERCC1-XPF, but additional components have not been excluded. The most complex and difficult to analyze factor is TFIIH, which has a 6-subunit core (XPB, XPD, p44, p34, p52, p62) and a 3-subunit kinase (CAK). TFIIH has roles both in basal transcription initiation and in DNA repair, and several inherited human disorders are associated with mutations in TFIIH subunits. To identify the forms of TFIIH that can function in repair, recombinant XPA, RPA, XPC-hHR23B, XPG, and ERCC1-XPF were combined with TFIIH fractions purified from HeLa cells. Repair activity coeluted with the peak of TFIIH and with transcription activity. TFIIH from cells with XPB or XPD mutations was defective in supporting repair, whereas TFIIH from spinal muscular atrophy cells with a deletion of one p44 gene was active. Recombinant TFIIH also functioned in repair, both a 6- and a 9-subunit form containing CAK. The CAK kinase inhibitor H-8 improved repair efficiency, indicating that CAK can negatively regulate NER by phosphorylation. The 15 recombinant polypeptides define the minimal set of proteins required for dual incision of DNA containing a cisplatin adduct. Complete repair was achieved by including highly purified human DNA polymerase delta or epsilon, PCNA, RFC, and DNA ligase I in reaction mixtures, reconstituting adduct repair for the first time with recombinant incision factors and human replication proteins.
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Affiliation(s)
- S J Araújo
- Imperial Cancer Research Fund (ICRF), Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, UK
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84
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Bradsher J, Coin F, Egly JM. Distinct roles for the helicases of TFIIH in transcript initiation and promoter escape. J Biol Chem 2000; 275:2532-8. [PMID: 10644710 DOI: 10.1074/jbc.275.4.2532] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To provide an explanation of some clinical features observed within rare xeroderma pigmentosum (XP) patients and to further define the role of XPB, XPD, and cdk7, the three enzymatic subunits of TFIIH, in the transcription reaction, we have examined two defined enzymatic steps: phosphodiester bond formation and promoter escape. We provide evidence that the XPB helicase plays a dominant role in initiation, whereas the XPD helicase plays a minor contributing role in this step. The cyclin-activating kinase subcomplex of TFIIH improves the efficiency of initiation, but this involves only the structural contributions of cyclin-activating kinase rather than enzymatic activity. We demonstrate that XPB patient-derived mutants in TFIIH suffer from defects in initiation. Moreover, mutant analysis shows that in addition to its crucial role in initiation, the XPB helicase plays a critical enzymatic role in the promoter escape, whereas XPD plays an important structural role in the promoter escape process. Finally, using patient-derived mutations in TFIIH, we demonstrate deficiencies in promoter escape for both mutants of the class that suffer from combined xeroderma pigmentosum/Cockayne's syndrome.
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Affiliation(s)
- J Bradsher
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, B.P.163, 67404 Illkirch Cedex, C.U. de Strasbourg, France
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85
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Moreland RJ, Tirode F, Yan Q, Conaway JW, Egly JM, Conaway RC. A role for the TFIIH XPB DNA helicase in promoter escape by RNA polymerase II. J Biol Chem 1999; 274:22127-30. [PMID: 10428772 DOI: 10.1074/jbc.274.32.22127] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TFIIH is an RNA polymerase II transcription factor that performs ATP-dependent functions in both transcription initiation, where it catalyzes formation of the open complex, and in promoter escape, where it suppresses arrest of the early elongation complex at promoter-proximal sites. TFIIH possesses three known ATP-dependent activities: a 3' --> 5' DNA helicase catalyzed by its XPB subunit, a 5' --> 3' DNA helicase catalyzed by its XPD subunit, and a carboxyl-terminal domain (CTD) kinase activity catalyzed by its CDK7 subunit. In this report, we exploit TFIIH mutants to investigate the contributions of TFIIH DNA helicase and CTD kinase activities to efficient promoter escape by RNA polymerase II in a minimal transcription system reconstituted with purified polymerase and general initiation factors. Our findings argue that the TFIIH XPB DNA helicase is primarily responsible for preventing premature arrest of early elongation intermediates during exit of polymerase from the promoter.
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Affiliation(s)
- R J Moreland
- Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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86
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Abstract
Recently, there has been a convergence of fields studying the processing of DNA, such as transcription, replication, and repair. This convergence has been centered around the packaging of DNA in chromatin. Chromatin structure affects all aspects of DNA processing because it modulates access of proteins to DNA. Therefore, a central theme has become the mechanism(s) for accessing DNA in chromatin. It seems likely that mechanisms involved in one of these processes may also be used in others. For example, the discovery of transcriptional coactivators with histone acetyltransferase activity and chromatin remodeling complexes has provided possible mechanisms required for efficient repair of DNA in chromatin.
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Affiliation(s)
- M Meijer
- Department of Biochemistry and biophysics, Washington State University, Pullman, USA
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87
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Reinberg D, Orphanides G, Ebright R, Akoulitchev S, Carcamo J, Cho H, Cortes P, Drapkin R, Flores O, Ha I, Inostroza JA, Kim S, Kim TK, Kumar P, Lagrange T, LeRoy G, Lu H, Ma DM, Maldonado E, Merino A, Mermelstein F, Olave I, Sheldon M, Shiekhattar R, Zawel L. The RNA polymerase II general transcription factors: past, present, and future. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1999; 63:83-103. [PMID: 10384273 DOI: 10.1101/sqb.1998.63.83] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- D Reinberg
- Howard Hughes Medical Institute, Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 0885, USA
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88
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Coin F, Egly JM. Ten years of TFIIH. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1999; 63:105-10. [PMID: 10384274 DOI: 10.1101/sqb.1998.63.105] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- F Coin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
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89
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Bochar DA, Pan ZQ, Knights R, Fisher RP, Shilatifard A, Shiekhattar R. Inhibition of transcription by the trimeric cyclin-dependent kinase 7 complex. J Biol Chem 1999; 274:13162-6. [PMID: 10224071 DOI: 10.1074/jbc.274.19.13162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclin-dependent kinase 7 (CDK7) can be isolated as a subunit of a trimeric kinase complex functional in activation of the mitotic promoting factor. In this study, we demonstrate that the trimeric cdk-activating kinase (CAK) acts as a transcriptional repressor of class II promoters and show that repression results from CAK impeding the entry of RNA polymerase II and basal transcription factor IIF into a competent preinitiation complex. This repression is independent of CDK7 kinase activity. We find that the p36/MAT1 subunit of CAK is required for transcriptional repression and the repression is independent of the promoter used. Our results demonstrate a central role for CAK in regulation of messenger RNA synthesis by either inhibition of RNA polymerase II-catalyzed transcription or stimulation of transcription through association with basal transcription repair factor IIH.
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Affiliation(s)
- D A Bochar
- Wistar Institute, Philadelphia, Pennsylvania 19104, USA
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90
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Coin F, Bergmann E, Tremeau-Bravard A, Egly JM. Mutations in XPB and XPD helicases found in xeroderma pigmentosum patients impair the transcription function of TFIIH. EMBO J 1999; 18:1357-66. [PMID: 10064601 PMCID: PMC1171225 DOI: 10.1093/emboj/18.5.1357] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
As part of TFIIH, XPB and XPD helicases have been shown to play a role in nucleotide excision repair (NER). Mutations in these subunits are associated with three genetic disorders: xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD). The strong heterogeneous clinical features observed in these patients cannot be explained by defects in NER alone. We decided to look at the transcriptional activity of TFIIH from cell lines of XP individuals. We set up an immunopurification procedure to isolate purified TFIIH from patient cell extracts. We demonstrated that mutations in two XP-B/CS patients decrease the transcriptional activity of the corresponding TFIIH by preventing promoter opening. The defect of XPB in transcription can be circumvented by artificial opening of the promoter. Western blot analysis and enzymatic assays indicate that XPD mutations affect the stoichiometric composition of TFIIH due to a weakness in the interaction between XPD-CAK complex and the core TFIIH, resulting in a partial reduction of transcription activity. This work, in addition to clarifying the role of the various TFIIH subunits, supports the current hypothesis that XP-B/D patients are more likely to suffer from transcription repair syndromes rather than DNA repair disorders alone.
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Affiliation(s)
- F Coin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, B.P.163, 67404 Illkirch Cedex, C.U. de Strasbourg, France
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91
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Wu L, Chen P, Hwang JJ, Barsky LW, Weinberg KI, Jong A, Starnes VA. RNA antisense abrogation of MAT1 induces G1 phase arrest and triggers apoptosis in aortic smooth muscle cells. J Biol Chem 1999; 274:5564-72. [PMID: 10026172 DOI: 10.1074/jbc.274.9.5564] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human MAT1 gene (ménage à trois 1) is an assembly factor and a targeting subunit of cyclin-dependent kinase (CDK)-activating kinase. The novel mechanisms by which MAT1 forms an active CDK-activating kinase and determines substrate specificity of CDK7-cyclin H are involved in the cell cycle, DNA repair, and transcription. Hyperplasia of vascular smooth muscle cells (SMC) is a fundamental pathologic feature of luminal narrowing in vascular occlusive diseases, and nothing is yet known regarding the cell cycle phase specificity of the MAT1 gene in its involvement in SMC proliferation. To investigate such novel regulatory pathways, MAT1 expression was abrogated by retrovirus-mediated gene transfer of antisense MAT1 RNA in cultured rat aortic SMCs. We show that abrogation of MAT1 expression retards SMC proliferation and inhibits cell activation from a nonproliferative state. Furthermore, we have demonstrated that these effects are due to G1 phase arrest and apoptotic cell death. Our studies indicate a link between cell cycle control and apoptosis and reveal a potential mechanism for coupling the regulation of MAT1 with G1 exit and prevention of apoptosis.
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Affiliation(s)
- L Wu
- Division of Cardiothoracic Surgery, Childrens Hospital Los Angeles Research Institute, University of Southern California School of Medicine, Los Angeles, California 90027, USA.
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92
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Yin MB, Guo B, Panadero A, Frank C, Wrzosek C, Slocum HK, Rustum YM. Cyclin E-cdk2 activation is associated with cell cycle arrest and inhibition of DNA replication induced by the thymidylate synthase inhibitor Tomudex. Exp Cell Res 1999; 247:189-99. [PMID: 10047461 DOI: 10.1006/excr.1998.4346] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tomudex (ZD1694) is a specific antifolate-based thymidylate synthase inhibitor active in a variety of solid tumor malignancies. Studies were carried out in vitro to evaluate downstream molecular alterations induced as a consequence of the potent and sustained inhibition of thymidylate synthase by Tomudex. Twenty-four hours following the initial 2-h treatment with Tomudex, human A253 head and neck squamous carcinoma cells, not expressing p53 and p21(WAF1), were accumulated with DNA content characteristic of early S phase of the cell cycle with a concomitant reduction of cells in G1 and G2/M phases. The changes in cyclin and cdk protein expression and their kinase activities were examined in control and drug-treated A253 cells. Tomudex treatment resulted in the decrease in p27(kip1) expression, with an increase in cyclin E and cdk2 protein expression and kinase activities 24 h after a 2-h exposure. Although cyclin A protein expression was markedly increased, cyclin A kinase activity was only slightly increased. Cyclin D1, cyclin B, cdk4, and cdc2 protein expression and kinase activities remain constant. Lack of activation of cyclin A- and B-cdc2 was associated with a reduced proportion of cells in G2/M phases. Increased cyclin E-cdk2 protein expression was accompanied by the inhibition of DNA synthesis, with a decrease in E2F-1 expression. These results propose that cyclin E-cdk2 kinase can negatively regulate DNA replication. The studies with dThyd rescue from cyclin E-cdk2 protein overexpression and growth inhibition by Tomudex indicate that increased cyclin E-cdk2 protein expression is associated with effective inhibition of thymidylate synthase and resultant dNTP pool imbalance. Provision of dThyd more than 24 h after exposure to Tomudex allowed cells to replicate DNA for a single cycle back to G1, but did not prevent the profound growth-inhibitory effect manifested in the following 5 days. Tomudex treatment resulted in a time-dependent induction of the megabase DNA fragments, followed by secondary 50- to 300-kb DNA fragmentation. The 50- to 300-kb DNA fragmentation may be derived from the inhibition of DNA synthesis associated with cyclin E-cdk2 activation. These results suggest that the megabase DNA fragmentation is induced as a consequence of inhibition of thymidylate synthase by Tomudex and kilobase DNA fragmentation may correlate with the reduction of p27(kip1) expression and the increase in cyclin E and cdk2 kinase activities. Activation of cyclin E and cdk2 kinases allows cells to transit from G1 to S phase accompanied by the inhibition of DNA synthesis. The changes in cell cycle regulatory proteins associated with growth inhibition and DNA damage by Tomudex are not p53 dependent.
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Affiliation(s)
- M B Yin
- Grace Cancer Drug Center, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York, 14263, USA
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93
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Frit P, Bergmann E, Egly JM. Transcription factor IIH: a key player in the cellular response to DNA damage. Biochimie 1999; 81:27-38. [PMID: 10214907 DOI: 10.1016/s0300-9084(99)80035-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
TFIIH (transcription factor IIH) is a multiprotein complex consisting of nine subunits initially characterized as a basal transcription factor required for initiation of protein-coding RNA synthesis. TFIIH was the first transcription factor shown to harbor several enzymatic activities, likely indicative of functional complexity. This intricacy was further emphasized with the cloning of the genes encoding the different subunits which disclosed direct connections between transcription, DNA repair and cell cycle regulation. In this review, we emphasize those functions of TFIIH involved in DNA repair, as well as their relationship to TFIIH's roles in transcription, cell cycle control and apoptosis. These connections may prove to be essential for the cellular response to DNA damage.
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Affiliation(s)
- P Frit
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis-Pasteur, Strasbourg, Illkirch, France
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94
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Tirode F, Busso D, Coin F, Egly JM. Reconstitution of the transcription factor TFIIH: assignment of functions for the three enzymatic subunits, XPB, XPD, and cdk7. Mol Cell 1999; 3:87-95. [PMID: 10024882 DOI: 10.1016/s1097-2765(00)80177-x] [Citation(s) in RCA: 237] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
To understand the initiation of the transcription of protein-coding genes, we have dissected the role of the basal transcription/DNA repair factor TFIIH. Having succeeded in reconstituting a functionally active TFIIH from baculovirus recombinant polypeptides, we were able to analyze the role of XPB, XPD, and cdk7 subunits in the transcription reaction. Designing mutated recombinant subunits, we show that the XPB helicase is absolutely required for transcription to open the promoter around the start site whereas the XPD helicase, which is dispensable, stimulates transcription and allows the CAK complex to be anchored to TFIIH. In addition, we also show that cdk7 may phosphorylate the carboxy-terminal domain (CTD) of RNA pol II in the absence of promoter opening.
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Affiliation(s)
- F Tirode
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, C. U. de Strasbourg, France
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95
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Memili E, First NL. Developmental changes in RNA polymerase II in bovine oocytes, early embryos, and effect of alpha-amanitin on embryo development. Mol Reprod Dev 1998; 51:381-9. [PMID: 9820196 DOI: 10.1002/(sici)1098-2795(199812)51:4<381::aid-mrd4>3.0.co;2-g] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Development of mammalian early embryos relies on stored maternal messenger RNAs (mRNAs) that have been synthesized during oogenesis until embryonic genome activation. Although embryonic genome acti vation in bovine embryos has been proposed to start at the late 4-cell stage, recent evidences suggest that embryonic genome activation starts earlier than the 4-cell stage, and molecular details of this event are not known. RNA polymerase II in eukaryotes is responsible for transcription of mRNA and most of the small nuclear RNAs. The unphosphorylated form of RNA polymerase II (IIA) has been shown to function in transcriptional initiation, and the hyperphosphorylated form (IIO) functions in translational elongation and mRNA splicing. In this study, we examined the changes in the amount of RNA polymerase IIA by immunoblotting in immature oocytes; mature oocytes; and 2-, 4- and 8-cell bovine embryos. We also examined the levels of IIO and the multiple intermediately phosphorylated form in the same oocytes and embryos. The IIA reached the highest level at the 2-cell stage and decreased gradually at the 4- and 8-cell stages, and IIO was at very low levels in mature oocytes and 2-cell stage embryos and was not detectable at later stages. The multiple intermediately phosphorylated form was present at the highest level in mature oocytes and was detectable at the other stages. We demonstrate that RNA polymerase IIA, which is responsible for initiation of transcription, is present in oocytes and preimplantation embryos and reaches the highest levels in the 2-cell stage embryos. Inhibition of RNA polymerase II-dependent transcription during any of the first four embryonic cell cycles has detrimental effects on progression of embryonic development beyond the 16-cell stage, indicating the importance of early transcripts for continuation of development. The results indicate that expression of all the genes whose transcription is inhibited by alpha-amanitin is essential for embryo development.
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Affiliation(s)
- E Memili
- Department of Animal Sciences, University of Wisconsin-Madison, 53706, USA.
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96
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Akoulitchev S, Reinberg D. The molecular mechanism of mitotic inhibition of TFIIH is mediated by phosphorylation of CDK7. Genes Dev 1998; 12:3541-50. [PMID: 9832506 PMCID: PMC317239 DOI: 10.1101/gad.12.22.3541] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
TFIIH is a multisubunit complex, containing ATPase, helicases, and kinase activities. Functionally, TFIIH has been implicated in transcription by RNA polymerase II (RNAPII) and in nucleotide excision repair. A member of the cyclin-dependent kinase family, CDK7, is the kinase subunit of TFIIH. Genetically, CDK7 homologues have been implicated in transcription in Saccharomyces cerevisiae, and in mitotic regulation in Schizosaccharomyces pombe. Here we show that in mitosis the CDK7 subunit of TFIIH and the largest subunit of RNAPII become hyperphosphorylated. MPF-induced phosphorylation of CDK7 results in inhibition of the TFIIH-associated kinase and transcription activities. Negative and positive regulation of TFIIH requires phosphorylation within the T-loop of CDK7. Our data establishes TFIIH and its subunit CDK7 as a direct link between the regulation of transcription and the cell cycle.
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Affiliation(s)
- S Akoulitchev
- Howard Hughes Medical Institute, Division of Nucleic Acids Enzymology, Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854-5635 USA
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97
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Abstract
The cell cycle is a complex process that involves numerous regulatory proteins that direct the cell through a specific sequence of events culminating in mitosis and the production of two daughter cells. Central to this process are the cyclin-dependent kinases (cdks), which complex with the cyclin proteins. These proteins regulate the cell's progression through the stages of the cell cycle and are in turn regulated by numerous proteins, including p53, p21, p16, and cdc25. Downstream targets of cyclin-cdk complexes include pRb and E2F. The cell cycle can be altered to the advantage of many viral agents, most notably polyomaviruses, papillomaviruses, and adenoviruses. The cell cycle often is dysregulated in neoplasia due to alterations either in oncogenes that indirectly affect the cell cycle or in tumor suppressor genes or oncogenes that directly impact cell cycle regulation, such as pRb, p53, p16, cyclin D1, or mdm-2. The cell cycle has become an intense subject of research in recent years. This research has led to the development of techniques useful for the determination of the effects of drugs and toxins on the cell cycle. Any drug or toxin with DNA damaging ability would be expected to alter cell cycle progression, and therefore, the cell cycle should be considered in the design of studies using such chemicals. With the appropriate techniques, cell cycle alterations may also be detected in tissue sections. Because of the ubiquitous nature of the cell cycle, it deserves consideration in the design and interpretation of studies in a wide variety of disciplines.
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98
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Tanaka T, Tatsuno I, Noguchi Y, Uchida D, Oeda T, Narumiya S, Yasuda T, Higashi H, Kitagawa M, Nakayama K, Saito Y, Hirai A. Activation of cyclin-dependent kinase 2 (Cdk2) in growth-stimulated rat astrocytes. Geranylgeranylated Rho small GTPase(s) are essential for the induction of cyclin E gene expression. J Biol Chem 1998; 273:26772-8. [PMID: 9756921 DOI: 10.1074/jbc.273.41.26772] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The role of the mevalonate cascade in the control of cell cycle progression in astrocytes has been investigated. Serum stimulation of rat astrocytes in primary culture induces the expression of cyclin E followed by the activation of cyclin-dependent kinase 2 (Cdk2) during G1/S transition. The expression of p27, cyclin D1, and the activities of Cdk4 and Cdk-activating kinase (CAK), composed of Cdk7 and cyclin H, were not affected. Serum did, however, stimulate the expression of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase mRNA at mid-G1 phase. Moreover, an inhibitor of HMG-CoA reductase, pravastatin, reduced cyclin E expression and Cdk2 activation and caused G1 arrest in the astrocytes. In contrast, mevalonate and its metabolite, geranylgeranylpyrophosphate (GGPP) but not farnesylpyrophosphate (FPP), reversed the inhibitory effects of pravastatin on cyclin E expression and Cdk2 activation and allowed G1/S transition. Rho small GTPase(s) were geranylgeranylated and translocated to membranes in the presence of GGPP during G1/S transition. The effect of GGPP on cyclin E expression was abolished by botulinum C3 exoenzyme, which specifically inactivates Rho. These data indicate that geranylgeranylated Rho small GTPase(s) are essential for the induction of cyclin E expression, Cdk2 activation, and G1/S transition in rat astrocytes.
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Affiliation(s)
- T Tanaka
- Second Department of Internal Medicine, Chiba University School of Medicine, Chiba 260,, Japan.
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99
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Coin F, Marinoni JC, Rodolfo C, Fribourg S, Pedrini AM, Egly JM. Mutations in the XPD helicase gene result in XP and TTD phenotypes, preventing interaction between XPD and the p44 subunit of TFIIH. Nat Genet 1998; 20:184-8. [PMID: 9771713 DOI: 10.1038/2491] [Citation(s) in RCA: 263] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In most cases, xeroderma pigmentosum group D (XP-D) and trichothiodystrophy (TTD) patients carry mutations in the carboxy-terminal domain of the evolutionarily conserved helicase XPD, which is one of the subunits of the transcription/repair factor TFIIH (refs 1,2). In this study, we demonstrate that XPD interacts specifically with p44, another subunit of TFIIH, and that this interaction results in the stimulation of 5'-->3' helicase activity. Mutations in the XPD C-terminal domain, as found in most patients, prevent the interaction with p44, thus explaining the decrease in XPD helicase activity and the nucleotide excision repair (NER) defect.
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Affiliation(s)
- F Coin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, B.P.163, Illkirch, C.U. de Strasbourg, France
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100
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Wu SY, Kershnar E, Chiang CM. TAFII-independent activation mediated by human TBP in the presence of the positive cofactor PC4. EMBO J 1998; 17:4478-90. [PMID: 9687514 PMCID: PMC1170779 DOI: 10.1093/emboj/17.15.4478] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
TFIID is a multiprotein complex comprised of the TATA-binding protein (TBP) and an array of TBP-associated factors (TAFIIs). Whereas TBP is sufficient for basal transcription in conjunction with other general transcription factors and RNA polymerase II, TAFIIs are additionally required for activator-dependent transcription in mammalian cell-free transcription systems. However, recent in vivo studies carried out in yeast suggest that TAFIIs are not globally required for activator function. The discrepancy between in vivo yeast studies and in vitro mammalian cell-free systems remains to be resolved. In this study, we describe a mammalian cell-free transcription system reconstituted with only recombinant proteins and epitope-tagged multiprotein complexes. Transcriptional activation can be recapitulated in this highly purified in vitro transcription system in the absence of TAFIIs. This TBP-mediated activation is not induced by human mediator, another transcriptional coactivator complex potentially implicated in activator response. In contrast, general transcription factors TFIIH and TFIIA play a significant role in TBP-mediated activation, which can be detected in vitro with Gal4 fusion proteins containing various transcriptional activation domains. Our data, therefore, suggest that TFIIH and TFIIA can mediate activator function in the absence of TAFIIs.
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Affiliation(s)
- S Y Wu
- Department of Biochemistry, University of Illinois, Urbana 61801, USA
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