101
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Pan G, Aso T, Greenblatt J. Interaction of elongation factors TFIIS and elongin A with a human RNA polymerase II holoenzyme capable of promoter-specific initiation and responsive to transcriptional activators. J Biol Chem 1997; 272:24563-71. [PMID: 9305922 DOI: 10.1074/jbc.272.39.24563] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Affinity chromatography on columns containing the immobilized monomeric transcriptional elongation factor TFIIS or the essential large subunit, Elongin A, of the trimeric elongation factor, Elongin, was used to purify a human RNA polymerase II holoenzyme from HeLa whole cell extract. This holoenzyme contained nearstoichiometric amounts of all the general transcription factors, TFIIB, TFIID (TBP + TAFIIs), TFIIE, TFIIF, and TFIIH, required to accurately initiate transcription in vitro at the adenovirus major late promoter. It behaved as a large complex, slightly smaller than 70 S ribosomes, during gel filtration chromatography, and contained nearly half the TFIID that was present in the extract used for the affinity chromatography. It also contained the cyclin-dependent kinase CDK8, a human homologue of the Saccharomyces cerevisiae holoenzyme subunit SRB10, and many other polypeptides. Efficient interaction of holoenzyme with TFIIS or Elongin A required only the amino-terminal region of either protein. These regions are similar in amino acid sequence but dispensable for TFIIS or Elongin to regulate elongation in vitro by highly purified RNA polymerase II. The transcriptional activators GAL4-VP16 and GAL4-Sp1 activated transcription in vitro by purified holoenzyme in the absence of any additional factors.
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Affiliation(s)
- G Pan
- Banting and Best Department of Medical Research and Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario M5G 1L6, Canada
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102
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Nocentini S, Coin F, Saijo M, Tanaka K, Egly JM. DNA damage recognition by XPA protein promotes efficient recruitment of transcription factor II H. J Biol Chem 1997; 272:22991-4. [PMID: 9287294 DOI: 10.1074/jbc.272.37.22991] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The human basal transcription factor IIH (TFIIH) is an essential component of the nucleotide excision repair machinery. TFIIH is required for reaction steps concomitant with or prior to the formation of dual incisions in the damaged DNA strand. To understand the mechanism underlying the recruitment of TFIIH to DNA damage sites we have analyzed i) the direct affinity of TFIIH for damaged or undamaged DNA and ii) the interaction of TFIIH with XPA.DNA complexes, formed using unirradiated or UV-irradiated DNA. Filter binding assays showed that TFIIH has some affinity for the DNA, but in contrast to XPA, does not show any preference for UV-irradiated DNA. Pull-down experiments demonstrated that TFIIH binds to XPA.DNA complexes in an UV damage-dependent manner by a direct protein-protein interaction with XPA. We propose that an enhancement of the affinity of XPA protein for TFIIH could arise from conformational changes of XPA when it binds to UV lesions on the DNA.
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Affiliation(s)
- S Nocentini
- CNRS UMR 218 et LRC no. 1 du CEA, Institut Curie, Section de Recherche, 26 rue d'Ulm, 75248 Paris Cedex 05, France
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103
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Taylor EM, Broughton BC, Botta E, Stefanini M, Sarasin A, Jaspers NG, Fawcett H, Harcourt SA, Arlett CF, Lehmann AR. Xeroderma pigmentosum and trichothiodystrophy are associated with different mutations in the XPD (ERCC2) repair/transcription gene. Proc Natl Acad Sci U S A 1997; 94:8658-63. [PMID: 9238033 PMCID: PMC23065 DOI: 10.1073/pnas.94.16.8658] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The xeroderma pigmentosum group D (XPD) protein has a dual function, both in nucleotide excision repair of DNA damage and in basal transcription. Mutations in the XPD gene can result in three distinct clinical phenotypes, XP, trichothiodystrophy (TTD), and XP with Cockayne syndrome. To determine if the clinical phenotypes of XP and TTD can be attributed to the sites of the mutations, we have identified the mutations in a large group of TTD and XP-D patients. Most sites of mutations differed between XP and TTD, but there are three sites at which the same mutation is found in XP and TTD patients. Since the corresponding patients were all compound heterozygotes with different mutations in the two alleles, the alleles were tested separately in a yeast complementation assay. The mutations which are found in both XP and TTD patients behaved as null alleles, suggesting that the disease phenotype was determined by the other allele. If we eliminate the null mutations, the remaining mutagenic pattern is consistent with the site of the mutation determining the phenotype.
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Affiliation(s)
- E M Taylor
- Medical Research Council Cell Mutation Unit, Sussex University, Falmer, Brighton BN1 9RR, United Kingdom
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104
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Kim N, Kage K, Matsuda F, Lefranc MP, Storb U. B lymphocytes of xeroderma pigmentosum or Cockayne syndrome patients with inherited defects in nucleotide excision repair are fully capable of somatic hypermutation of immunoglobulin genes. J Exp Med 1997; 186:413-9. [PMID: 9236193 PMCID: PMC2198998 DOI: 10.1084/jem.186.3.413] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/1997] [Revised: 05/19/1997] [Indexed: 02/04/2023] Open
Abstract
Recent experiments have strongly suggested that the process of somatic mutation is linked to transcription initiation. It was postulated that a mutator factor loads onto the RNA polymerase and, during elongation, causes transcriptional arrest that activates DNA repair, thus occasionally causing errors in the DNA sequence. We report the analysis of the role of one of the known DNA repair systems, nucleotide excision repair (NER), in somatic mutation. Epstein-Barrvirus-transformed B cells from patients with defects in NER (XP-B, XP-D, XP-V, and CS-A) were studied. Their heavy and light chain genes show a high frequency of point mutations in the variable (V), but not in the constant (C) regions. This suggests that these B cells can undergo somatic hypermutation despite significant defects in NER. Thus, it is doubtful that NER is an essential part of the mechanism of somatic hypermutation of Ig genes. As an aside, NER seems also not involved in Ig gene switch recombination.
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Affiliation(s)
- N Kim
- Department of Biochemistry, University of Chicago, Illinois 60637, USA
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105
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Alaoui-Jamali MA, Yen L. The role of ErbB-2 tyrosine kinase receptor in cellular intrinsic chemoresistance: mechanisms and implications. Biochem Cell Biol 1997. [DOI: 10.1139/o97-060] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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106
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Rochette-Egly C, Adam S, Rossignol M, Egly JM, Chambon P. Stimulation of RAR alpha activation function AF-1 through binding to the general transcription factor TFIIH and phosphorylation by CDK7. Cell 1997; 90:97-107. [PMID: 9230306 DOI: 10.1016/s0092-8674(00)80317-7] [Citation(s) in RCA: 238] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The activity of the N-terminal activation function AF-1 of RAR alpha1 is abrogated upon mutation of a phosphorylatable serine residue (Ser-77). Recombinant RAR alpha was phosphorylated by a variety of proline-directed protein kinases in vitro. However, only the coexpression of cdk7 stimulated Ser-77 phosphorylation in vivo and enhanced transactivation by RAR alpha, but not by a S77A RAR mutant. Both free CAK (cdk7, cyclin H, MAT1) and the CAK-containing general transcription factor TFIIH phosphorylated Ser-77 in vitro. Furthermore RAR alpha bound free CAK and purified TFIIH in vitro, and RAR alpha-TFIIH complexes could be isolated from HeLa nuclear extracts. These findings represent the first example of activation of a transactivator through binding to and phosphorylation by a general transcription factor.
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Affiliation(s)
- C Rochette-Egly
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université Louis Pasteur, Collège de France, Illkirch, Strasbourg
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107
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Marinoni JC, Rossignol M, Egly JM. Purification of the transcription/repair factor TFIIH and evaluation of its associated activities in vitro. Methods 1997; 12:235-53. [PMID: 9237168 DOI: 10.1006/meth.1997.0476] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We describe here the methodology developed in our laboratory to study the role of TFIIH, a multisubunit protein complex, in the various mechanisms of cell life: transcription, DNA repair, and cell cycle regulation. Protocols are given to purify TFIIH and to study its various enzymatic activities as well as its transcription and nucleotide excision repair activities.
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Affiliation(s)
- J C Marinoni
- Institut de Biologie et Génétique Moléculaire et Cellulaire, UPR 6520 (CNRS), Unité 184 (INSERM), Illkirch, France
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108
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Jordan P, Cunha C, Carmo-Fonseca M. The cdk7-cyclin H-MAT1 complex associated with TFIIH is localized in coiled bodies. Mol Biol Cell 1997; 8:1207-17. [PMID: 9243502 PMCID: PMC276147 DOI: 10.1091/mbc.8.7.1207] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
TFIIH is a general transcription factor for RNA polymerase II that in addition is involved in DNA excision repair. TFIIH is composed of eight or nine subunits and we show that at least four of them, namely cdk7, cyclin H, MAT1, and p62 are localized in the coiled body, a distinct subnuclear structure that is transcription dependent and highly enriched in small nuclear ribonucleoproteins. Although coiled bodies do not correspond to sites of transcription, in vivo incorporation of bromo-UTP shows that they are surrounded by transcription foci. Immunofluorescence analysis using antibodies directed against the essential repair factors proliferating cell nuclear antigen and XPG did not reveal labeling of the coiled body in either untreated cells or cells irradiated with UV light, arguing that coiled bodies are probably not involved in DNA repair mechanisms. The localization of cyclin H in the coiled body was predominantly detected during the G1 and S-phases of the cell cycle, whereas in G2 coiled bodies were very small or not detected. Finally, both cyclin H and cdk7 did not colocalize with P80 coilin after disruption of the coiled body, indicating that these proteins are specifically targeted to the small nuclear ribonucleoprotein-containing domain.
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Affiliation(s)
- P Jordan
- Institute of Histology and Embryology, Faculty of Medicine, University of Lisbon, Portugal
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109
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Weeda G, Rossignol M, Fraser RA, Winkler GS, Vermeulen W, van 't Veer LJ, Ma L, Hoeijmakers JH, Egly JM. The XPB subunit of repair/transcription factor TFIIH directly interacts with SUG1, a subunit of the 26S proteasome and putative transcription factor. Nucleic Acids Res 1997; 25:2274-83. [PMID: 9173976 PMCID: PMC146752 DOI: 10.1093/nar/25.12.2274] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Mutations in the basal transcription initiation/DNA repair factor TFIIH are responsible for three human disorders: xeroderma pigmentosum (XP), cockayne syndrome (CS) and trichothiodystrophy (TTD). The non-repair features of CS and TTD are thought to be due to a partial inactivation of the transcription function of the complex. To search for proteins whose interaction with TFIIH subunits is disturbed by mutations in patients we used the yeast two-hybrid system and report the isolation of a novel XPB interacting protein, SUG1. The interaction was validated in vivo and in vitro in the following manner. (i) SUG1 interacts with XPB but not with the other core TFIIH subunits in the two-hybrid assay. (ii) Physical interaction is observed in a baculovirus co-expression system. (iii) In fibroblasts under non-overexpression conditions a portion of SUG1 is bound to the TFIIH holocomplex as deduced from co-purification, immunopurification and nickel-chelate affinity chromatography using functional tagged TFIIH. Furthermore, overexpression of SUG1 in normal fibroblasts induced arrest of transcription and a chromatin collapse in vivo. Interestingly, the interaction was diminished with a mutant form of XPB, thus providing a potential link with the clinical features of XP-B patients. Since SUG1 is an integral component of the 26S proteasome and may be part of the mediator, our findings disclose a SUG1-dependent link between TFIIH and the cellular machinery involved in protein modelling/degradation.
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Affiliation(s)
- G Weeda
- Department of Cell Biology, Medical Genetics Center, Erasmus University, Rotterdam, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
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110
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Affiliation(s)
- P A Jeggo
- MRC Cell Mutation Unit, University of Sussex, Brighton, UK.
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111
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Prado F, Piruat JI, Aguilera A. Recombination between DNA repeats in yeast hpr1delta cells is linked to transcription elongation. EMBO J 1997; 16:2826-35. [PMID: 9184227 PMCID: PMC1169891 DOI: 10.1093/emboj/16.10.2826] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The induction of recombination by transcription activation has been documented in prokaryotes and eukaryotes. Unwinding of the DNA duplex, disruption of chromatin structure or changes in local supercoiling associated with transcription can be indirectly responsible for the stimulation of recombination. Here we provide genetic and molecular evidence for a specific mechanism of stimulation of recombination by transcription. We show that the induction of deletions between repeats in hpr1delta cells of Saccharomyces cerevisiae is linked to transcription elongation. Molecular analysis of different direct repeat constructs reveals that deletions induced by hpr1delta are specific for repeat constructs in which transcription initiating at an external promoter traverses particular regions of the DNA flanked by the repeats. Transcription becomes HPR1 dependent when elongating through such regions. Both the induction of deletions and the HPR1 dependence of transcription were abolished when a strong terminator was used to prevent transcription from proceeding through the DNA region flanked by the repeats. In contrast to previously reported cases of transcription-induced recombination, there was no correlation between high levels of transcripts and high levels of recombination. Our study provides evidence that direct repeat recombination can be induced by transcriptional elongation.
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Affiliation(s)
- F Prado
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Spain
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112
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van der Horst GT, van Steeg H, Berg RJ, van Gool AJ, de Wit J, Weeda G, Morreau H, Beems RB, van Kreijl CF, de Gruijl FR, Bootsma D, Hoeijmakers JH. Defective transcription-coupled repair in Cockayne syndrome B mice is associated with skin cancer predisposition. Cell 1997; 89:425-35. [PMID: 9150142 DOI: 10.1016/s0092-8674(00)80223-8] [Citation(s) in RCA: 268] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A mouse model for the nucleotide excision repair disorder Cockayne syndrome (CS) was generated by mimicking a truncation in the CSB(ERCC6) gene of a CS-B patient. CSB-deficient mice exhibit all of the CS repair characteristics: ultraviolet (UV) sensitivity, inactivation of transcription-coupled repair, unaffected global genome repair, and inability to resume RNA synthesis after UV exposure. Other CS features thought to involve the functioning of basal transcription/repair factor TFIIH, such as growth failure and neurologic dysfunction, are present in mild form. In contrast to the human syndrome, CSB-deficient mice show increased susceptibility to skin cancer. Our results demonstrate that transcription-coupled repair of UV-induced cyclobutane pyrimidine dimers contributes to the prevention of carcinogenesis in mice. Further, they suggest that the lack of cancer predisposition in CS patients is attributable to a global genome repair process that in humans is more effective than in rodents.
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Affiliation(s)
- G T van der Horst
- Medical Genetics Center, Department of Cell Biology and Genetics, Erasmus University Rotterdam, The Netherlands
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113
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114
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Abstract
The cyclin-dependent kinase (CDK)-activating kinase CAK has been proposed to function in the control of cell cycle progression, DNA repair and RNA polymerase II (pol II) transcription. Most CAK exists as complexes of three subunits: CDK7, cyclin H (CycH) and MAT1. This tripartite CAK occurs in a free form and in association with 'core' TFIIH, which functions in both pol II transcription and DNA repair. We investigated the substrate specificities of different forms of CAK. Addition of the MAT1 subunit to recombinant bipartite CDK7-CycH switched its substrate preference to favour the pol II large subunit C-terminal domain (CTD) over CDK2. We suggest that the MAT1 protein, previously shown to function as an assembly factor for CDK7-CycH, also acts to modulate CAK substrate specificity. The substrate specificities of natural TFIIH and free CAK were also compared. TFIIH had a strong preference for the CTD over CDK2 relative to free CAK. TFIIH, but not free CAK, could efficiently hyperphosphorylate the CTD. In the context of TFIIH, the kinase also acquired specificity for the general transcription factors TFIIE and TFIIF which were not recognized by free CAK. We conclude that the substrate preference of the CDK7-CycH kinase is governed by association with both MAT1 and 'core' TFIIH.
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Affiliation(s)
- K Y Yankulov
- Amgen Institute and Department of Medical Biophysics, University of Toronto, Ontario, Canada
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115
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Marinoni JC, Roy R, Vermeulen W, Miniou P, Lutz Y, Weeda G, Seroz T, Gomez DM, Hoeijmakers JH, Egly JM. Cloning and characterization of p52, the fifth subunit of the core of the transcription/DNA repair factor TFIIH. EMBO J 1997; 16:1093-102. [PMID: 9118947 PMCID: PMC1169708 DOI: 10.1093/emboj/16.5.1093] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
TFIIH is a multiprotein factor involved in transcription and DNA repair and is implicated in DNA repair/transcription deficiency disorders such as xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy. Eight out of the nine genes encoding the subunits forming TFIIH have already been cloned. We report here the identification, cDNA cloning and gene structure of the 52 kDa polypeptide and its homology with the yeast counterpart TFB2. This protein, along with p89/XPB, p62, p44 and p34, forms the core of TFIIH. Moreover, using in vitro reconstituted transcription and nucleotide excision repair (NER) assays and microinjection experiments, we demonstrate that p52 is directly involved in both transcription and DNA repair mechanisms in vitro and in vivo.
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MESH Headings
- Amino Acid Sequence
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/pharmacology
- Blotting, Western
- Chromosome Mapping
- Chromosomes, Human, Pair 6
- Cloning, Molecular
- DNA Repair
- Electrophoresis, Polyacrylamide Gel
- Fungal Proteins/chemistry
- Humans
- In Situ Hybridization, Fluorescence
- Microinjections
- Molecular Sequence Data
- Saccharomyces cerevisiae/chemistry
- Saccharomyces cerevisiae Proteins
- Sequence Alignment
- Sequence Analysis
- TATA-Binding Protein Associated Factors
- Transcription Factor TFIID
- Transcription Factor TFIIH
- Transcription Factors/chemistry
- Transcription Factors/genetics
- Transcription Factors/isolation & purification
- Transcription Factors/metabolism
- Transcription Factors, TFII
- Transcription, Genetic
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Affiliation(s)
- J C Marinoni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis Pasteur, Strasbourg, France
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116
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Bellier S, Dubois MF, Nishida E, Almouzni G, Bensaude O. Phosphorylation of the RNA polymerase II largest subunit during Xenopus laevis oocyte maturation. Mol Cell Biol 1997; 17:1434-40. [PMID: 9032270 PMCID: PMC231868 DOI: 10.1128/mcb.17.3.1434] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Xenopus laevis oogenesis is characterized by an active transcription which ceases abruptly upon maturation. To survey changes in the characteristics of the transcriptional machinery which might contribute to this transcriptional arrest, the phosphorylation status of the RNA polymerase II largest subunit (RPB1 subunit) was analyzed during oocyte maturation. We found that the RPB1 subunit accumulates in large quantities from previtellogenic early diplotene oocytes up to fully grown oocytes. The C-terminal domain (CTD) of the RPB1 subunit was essentially hypophosphorylated in growing oocytes from Dumont stage IV to stage VI. Upon maturation, the proportion of hyperphosphorylated RPB1 subunits increased dramatically and abruptly. The hyperphosphorylated RPB1 subunits were dephosphorylated within 1 h after fertilization or heat shock of the matured oocytes. Extracts from metaphase II-arrested oocytes showed a much stronger CTD kinase activity than extracts from prophase stage VI oocytes. Most of this kinase activity was attributed to the activated Xp42 mitogen-activated protein (MAP) kinase, a MAP kinase of the ERK type. Making use of artificial maturation of the stage VI oocyte through microinjection of a recombinant stable cyclin B1, we observed a parallel activation of Xp42 MAP kinase and phosphorylation of RPB1. Both events required protein synthesis, which demonstrated that activation of p34(cdc2)off kinase was insufficient to phosphorylate RPB1 ex vivo and was consistent with a contribution of the Xp42 MAP kinase to RPB1 subunit phosphorylation. These results further support the possibility that the largest RNA polymerase II subunit is a substrate of the ERK-type MAP kinases during oocyte maturation, as previously proposed during stress or growth factor stimulation of mammalian cells.
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Affiliation(s)
- S Bellier
- Génétique Moléculaire, URA 1302 CNRS, Ecole Normale Supérieure, Paris, France
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117
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Poterszman A, Andersen G, Busso D, Rossignol M, Egly JM, Thierry JC. Expression in Escherichia coli: purification and characterization of cyclin H, a subunit of the human general transcription/DNA repair factor TFIIH. Protein Expr Purif 1997; 9:153-8. [PMID: 9056480 DOI: 10.1006/prep.1996.0693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The human cyclin H, a protein normally associated with the cyclin-dependent kinase cdk7, was overexpressed in Escherichia coli using a T7 RNA polymerase expression system and further purified to apparent homogeneity. The purified recombinant cyclin H is similar to the endogenous one according to the following criteria: molecular weight, microsequencing and mass spectra studies, ability to interact with cdk7, and regulatory kinase activity. The scale-up of cyclin H purification is described.
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Affiliation(s)
- A Poterszman
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
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118
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Dubois MF, Vincent M, Vigneron M, Adamczewski J, Egly JM, Bensaude O. Heat-shock inactivation of the TFIIH-associated kinase and change in the phosphorylation sites on the C-terminal domain of RNA polymerase II. Nucleic Acids Res 1997; 25:694-700. [PMID: 9016617 PMCID: PMC146510 DOI: 10.1093/nar/25.4.694] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The C-terminal domain (CTD) of the RNA polymerase II largest subunit (RPB1) plays a central role in transcription. The CTD is unphosphorylated when the polymerase assembles into a preinitiation complex of transcription and becomes heavily phosphorylated during promoter clearance and entry into elongation of transcription. A kinase associated to the general transcription factor TFIIH, in the preinitiation complex, phosphorylates the CTD. The TFIIH-associated CTD kinase activity was found to decrease in extracts from heat-shocked HeLa cells compared to unstressed cells. This loss of activity correlated with a decreased solubility of the TFIIH factor. The TFIIH-kinase impairment during heat-shock was accompanied by the disappearance of a particular phosphoepitope (CC-3) on the RPB1 subunit. The CC-3 epitope was localized on the C-terminal end of the CTD and generated in vitro when the RPB1 subunit was phosphorylated by the TFIIH-associated kinase but not by another CTD kinase such as MAP kinase. In apparent discrepancy, the overall RPB1 subunit phosphorylation increased during heat-shock. The decreased activity in vivo of the TFIIH kinase might be compensated by a stress-activated CTD kinase such as MAP kinase. These results also suggest that heat-shock gene transcription may have a weak requirement for TFIIH kinase activity.
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Affiliation(s)
- M F Dubois
- Laboratoire de Génétique Moléculaire, URA CNRS 1302, Ecole Normale Supérieure, Paris, France
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119
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Evans E, Fellows J, Coffer A, Wood RD. Open complex formation around a lesion during nucleotide excision repair provides a structure for cleavage by human XPG protein. EMBO J 1997; 16:625-38. [PMID: 9034344 PMCID: PMC1169665 DOI: 10.1093/emboj/16.3.625] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human XPG nuclease makes the 3' incision during nucleotide excision repair of DNA. The enzyme cleaves model DNA bubble structures specifically near the junction of unpaired DNA with a duplex region. It is not yet known, however, whether an unpaired structure is an intermediate during actual DNA repair. We find here that XPG requires opening of >5 bp for efficient cleavage. To seek direct evidence for formation of an open structure around a lesion in DNA during a nucleotide excision repair reaction in vitro, KMnO4 footprinting experiments were performed on a damaged DNA molecule bearing a uniquely placed cisplatin adduct. An unwound open complex spanning approximately 25 nucleotides was observed that extended to the positions of 5' and 3' incision sites and was dependent on XPA protein and on ATP. Opening during repair occurred prior to strand incision by XPG.
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Affiliation(s)
- E Evans
- Imperial Cancer Research Fund, Clare Hall Laboratories, London, UK
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120
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Garriga J, Segura E, Mayol X, Grubmeyer C, Graña X. Phosphorylation site specificity of the CDC2-related kinase PITALRE. Biochem J 1996; 320 ( Pt 3):983-9. [PMID: 9003389 PMCID: PMC1218024 DOI: 10.1042/bj3200983] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PITALRE is a human protein kinase belonging to the cell division cycle 2 (CDC2) kinase family, and is the catalytic subunit of a multimeric complex that contains several cellular proteins. PITALRE complexes from several cell lines and tissues phosphorylate retinoblastoma protein and myelin basic protein (MBP). In the present work, we have found that MBP is phosphorylated by PITALRE complexes on both Ser and Thr residues. Two different antibodies raised to PITALRE purified virtually identical kinase activities, as analysed by MBP phosphopeptide mapping and phosphoamino acid analysis. We have identified the proline-directed residue Ser-162 of MBP as a major phosphorylation site for PITALRE. In addition, our results suggest that one of the two MBP proline-directed threonine residues, Thr-97, is also selectively phosphorylated by PITALRE. These data, together with analysis of different peptide substrates derived from sites on MBP that are phosphorylated by PITALRE, indicate that PITALRE is a Ser/Thr proline-directed kinase. In addition, our results show that PITALRE has a substrate site specificity distinguishable from those of the CDC2 and cyclin-dependent kinase 2 (CDK2).
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Affiliation(s)
- J Garriga
- Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
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