P. Hughes· E. Fanning· M. Kohiyama(Eds.}

DNA Replication: The Regulatory Mechanisms

With 137 Figures

Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Hong Kong Barcelona Budapest

Dr. Patrick Hughes Institut Jacques Monod, CNRS Universite Paris 7 2 place Jussieu 75251 Paris Cedex 05 France

Dr. Ellen Fanning Institut fUr Biochemie KarlstraBe 23 8000 Munchen 2 FRO

Dr. Masamichi Kohiyama Institut Jacques Monod, CNRS Universite Paris 7 2 place Jussieu 75251 Paris Cedex 05 France

ISBN-13: 978-3-642-76990-0 DOl: 10.1007/978-3-642-76988-7

e-ISBN-13: 978-3-642-76988-7

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© Springer-Verlag Berlin Heidelberg 1992 Softcover reprint of the hardcover 1 st edition 1992

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Preface

The discovery of DNA polymerase I by A. Kornberg marked the starting point of a molecular approach to the study of DNA replication, a key event in the cell cycle. Since then, many enzymes and a multiplicity of biochemical mechanisms, apparently involved in some aspect of the initiation or elongation of DNA chains, have been discovered. Today, we thus find ourselves with a considerable variety of mechanisms and molecules that control DNA replication. Although our knowledge is far from complete and many elusive regulatory molecules remain beyond our grasp, it was one of the hopes of this meeting that researchers might reflect together on the relevance of accumulated data on regulation of replication and discover common ground. Probably, this type of approach is nowhere more necessary than in the sphere of E.coli DNA replication where recent discoveries have both confirmed and surpassed the original "Replicon hypothesis" of Jacob and colleagues. In yeast and higher eucaryotes, the apparent redundancy in putative origins and initiators has made an estimation of the importance of each identified element difficult to access. In fact readers of these proceedings will appreciate that origin identification in mammalian chromosomes is still a controversial subject. On the other hand considerable advances have been made in our understanding of virus and phage DNA replication and this continues to deepen and broaden our understanding of the controls of cellular DNA replication. The unexpected role of heat shock proteins is a recent example. In assembling the contributions to this volume, we have attempted to avoid the usual dichotomy prokaryotes/eucaryotes in the hope that, as you slalom along the double helix, you may find a path intertwined and crisscrossed by trades from many systems.

PATRICK HUGHES ELLEN FANNING

MASAMICHI KOHIYAMA JULY 1991

Acknowledgements

We would like to thank the Human Frontier Science Program (HFSP) for financing this first meeting on the regulatory mechanisms of DNA replication. We would also like to thank FEBS for their support in supplying fellowships to young scientists to attend the conference. Also, a number of people have generously contributed their time and effort to the organization of the meeting and the preparation of this volume. These include the organizers Drs Eric Boye, Jun-ichi Tomizawa and Judith Campbell. We also appreciate the combined efforts of Irene Sorokine, Abderrahim Malki, Kamel Ben Mahrez, John Herrick and Martine Genotte in slide projection and organization.

Contents

Introduction

Regulation of Initiation of Chromosome Replication A. Kornberg ............................................................................................................................. 1

PART 1 : CELLULAR DNA REPLICATION

Cell cycle control of DNA replication

1. Escherichia coli strains in which the chromosome is replicated from origins other than oriC R. Bernander, Santanu Dasgupta and Kurt Nord~trom ........................................ 11

2. Dam methyltransferase in Escherichia coli : Effects of different enzymatic levels on DNA replication and cell growth E. Boye, Anita Lyngstadaas and Anders L0bner-Olesen ................................... 23

3. Further characterization of a DNA replication inhibitor from the cell membrane of Escherichia coli P. Hughes, Abderrahim Malki, John Herrick, Renee Kern and Masamichi Kohiyama ................................................................................................ 37

4. The involvement of cdc2 in cell cycle control of DNA replication in Xenopus egg extracts J. J. Blow and Paul Nurse .............................................................................................. .49

5. A gene of Saccharomyces cerevisiae probably involved in the coordination of chromatin replication and cell division U. Wintersberger and Anneliese Karwan ................................................................ 59

Origin identification in mammalian chromosomes

6. Origins of DNA replication and nucleosome segregation in mammalian chromosomes W. C. Burhans, Lyubomir T. Vassilev, Jiarui Wu, Jose M. Sago, Ferez S. Nallaseth and Melvin L. DePamphilis ....................................................... 73

7. Directions of DNA replication in yeast and mammalian cells J. A. Huberman, Dharani D. Dubey, Kevin A. Nawotka, George Russev, J. Aquiles Sanchez, Yeup Yoon and Maarten H.K. Linskens ............... 83

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8. The curi'Ous case 'Of the n'Ovel 2-D gel artifact B. J. Brewer ......................................................................................................................... 97

Origin structure. functi'On and m'Odificati'On

9. Structural and functi'Onal characteristics 'Of aut'On'Om'Ously replicating mammalian 'Origin-enriched sequences (Q.B.S.) M. Zannis-Hadj'Op'Oul'Os, C. E. Pears'On, D. Bell, D. Mah, M. McAlear and G. B. Price ............................................................................................ 107

10. Mutati'Ons affecting replicati'On 'Origin functi'On in yeast S. E. Kearsey and David Kipling ............................................................................... 117

11. R'Ole 'Of transcripti'Onal elements in activating 'Origins 'Of replicati'On Z.-S. Gu'O, Maria Wiek'Owski, Sadhan Majumder, Miriam Miranda and Melvin L. DePamphilis ........................................................................................... 129

12. Telomere replicati'On in Saccharomyces cerevisiae V. A. Zakian, S.-S. Wang and R. Wellinger ............................................................. 139

Injtiat'Or - replicati'On 'Origin rec'Ogniti'On

13. The r'Ole 'Of DnaA-DnaA b'Ox interacti'On in initiati'On 'Of chr'Om'Os'Omal replicati'On in Bacillus subtilis N. Ogasawara, Shigeki M'Oriya and Hir'Oshi Y'Oshikawa .................................. 151

14. DnaA pr'Otein mediated transcripti'On terminati'On in the GUA 'Operon 'Of Escherichia coli C. Schaefer, Andreas H'Olz and Walter Messer .................................................... 161

15. Screens f'Or pr'Oteins binding t'O the ARS c'Onsensus sequence J. F. Theis and Car'Ol S. Newl'On ................................................................................ 169

16. Pr'Otein-DNA interacti'On at yeast replicati'On 'Origins: an ARS c'Onsensus binding pr'Otein J. F. X. H'Ofmann and S.M. Gasser ................................................................................ 181

17. Genetic Analysis 'Of the r'Oles 'Of yeast ARS binding fact'Or I P. R. Rhode and J. L. Campbell.. .................................................................................. 193

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18. Proteins involved in ARS function in yeast B. K. Tye, V. Chang, C. Christ, R. Elble, S. Gibson, S. Passmore and H. yan ............................................................................................................................ 205

19. ARS binding factors from Saccharomyces cerevisiae J. F. X. Diffley and Bruce Stillman .......................................................................... 215

Initiator interactions with PNA polymerases and accessory proteins

20. Mutations within the minimal replicon of plasmid pPS10 increase its host range R. Giraldo, Margarita Martin, Marfa Elena Fernimdez-Tresguerres, Concepcion Nieto and Ramon Diaz ............................................................................ 225

21. Human type I DNA topoisomerase: Regulation of expression and function R. Knippers, Ch. Lambrecht, H. Romig, A. Richter and N. Kunze .................... 239

22. Holoenzyme forms of yeast DNA polymerases ~ and E

P. M. J. Burgers .................................................................................................................. 251

23. The pol1 and pol3 DNA synthesis genes in fission yeast Schizosaccharomyces pombe G. Baldacci, D. Bouvier, V. Damagnez, G. Pignede and A-M. de Recondo ....................................................................................................... 261

24. DNA Polymerase ~ (POL3) of Saccharomyces cerevisiae G. Faye, F. Fabre, M. Simon, L. Giot, A. Boulet, P. Benit and A. Vassal. .................................................................................................................... 273

25. Genetic control of the DNA polymerase a-primase complex in the yeast Saccharomyces Cerevisiae P. Plevani, M. Foiani, S. Francesconi, A. Pizzagalli, C. Santocanale, M. Falconi Muzi, S. Piatti, A. Piseri, D. Derossi, M.P. Longhese, F. Locati, R. Tazzi, and G. Lucchini. .................... 285

PART 2 : VIRAL AND PLASMID DNA REPLICATION

Molecular interactions during protein primed initiation

26. Protein-primed replication of bacteriophage 029 DNA M. Salas, M. Serrano, C. Gutierrez, J.A. Esteban, MA Blasco, A. Be rn ad , J. Mendez, J.M. Lazaro, C. Garmendia, R. Freire, J. M. Sogo, J.M. Hermoso and L. Blanco .................. 295

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27. Molecular interactions at the adenovirus origin of DNA replication A.T. Hay, J. Bosher, A. Dawson and S. M. Temperley .......................................... 307

28. Analysis in vitro of mutations in the cloned precursor to the terminal protein (pTP) and the adenovirus DNA polymerase (ad Pol) genes J. A. Engler, Insil Joung, Jeffrey N. Fredman, Steven C. Pettit, Carl Abraham and Marshall S. Horwitz ................................................................. 321

29. The role of transcription factors in adenovirus DNA replication P. C. van der Vliet, C. P. Verrijzer, Y. M. Mul, J. AW. M. van Oosterhout and W. van Driel .......................................................... 331

Molecular interactions at origins on circular viral and phage DNA

30. The replication initiator protein of P1 is activated by two E. coli heat shock proteins, DnaJ and DnaK S. Wickner, Joel Hoskins and Keith Mc Kenney ................................................... 347

31. Bacteriophage Lambda DNA replication and the role of the universally conserved dnaK, dnaJ and grpE heat shock proteins K. Liberek, D. Skowyra, J. Marszalek, J. Osipiuk, M. Zylicz, D. Ang, A. Maddock, C. Johnson and C. Georgopoulos ...................................................... 359

32. SV40 DNA replication with purified proteins : functional interactions among the initiation proteins K. L. Collins, Lorne F. Erdile, Sandra K. Randall, Alicia A.A. Russo, Pamela A. Simancek, Christopher B. Umbricht, David M. Virshup, David H. Weinberg, Marc S. Wold and Thomas J. Kelly ................................... 369

33. Bovine RP-A functions in SV40 DNA replication in vitro, but bovine polymerase a-primase inhibits replication competitively C. Schneider, Dorothea von Winkler, Irene Dornreiter, Heinz-Peter Nasheuer, IIka Gilbert, Silke Dehde, Avril K. Arthur and Ellen Fanning ............................................................................................................ 385

34. Bovine Papillomavirus (BPV1) replication protein E1 : associated ATPase and binding to the viral E2 transactivator S. Santucci, Catherine Bonne-Andrea and Philippe Clertant... ................... 399

SUBJECT INDEX ............................................................................................................... .417

List of Contributors

Abraham, Carl. Department of Microbiology-Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

Ang, D. Division of Biophysics, Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk, POLAND.

Arthur, Avril K. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

Baldacci, G. C.N.R.S.-U.P.R.272, Laboratoire de Biologie Moleculaire de la Replication, 94800 Villejuif, FRANCE.

Bell, D. McGill Cancer Centre, McGill University, 3655 Drummond Street, Montreal,Quebec H3G lY6, CANADA.

Benit, P. Institut Curie-Biologie, Biitiment 110, Centre Universitaire, 91405 Orsay, FRANCE.

Bernad, A. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Bernander, Rolf. Department of Microbiology, University of Uppsala, The Biomedicale Center, Box 581, S-75123 Uppsala, SWEDEN.

Blanco, L. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Blasco, M.A. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Blow, J. Julian. ICRF Cell Cycle Group, Microbiology Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.

Bonne-Andrea, Catherine. University of Nice, INSERM U.273, Centre de Biochimie, Pare Valrose, 06034 Nice Cedex, FRANCE.

Bosher, J. Department of Biochemistry and Microbiology, University of St. Andrews, St. Andrews, Fife KY169AL. SCOTLAND.

Boulet, A. Institut Curie-Biologie, Biitiment 110, Centre Universitaire, 91405 Orsay, FRANCE.

Bouvier, D. C.N.R.S.-U.P.R.272, Laboratoire de Biologie Moleculaire de la Replication, 94800 Villejuif, FRANCE.

Boye, Erik. Department of Biophysics, Institute for Cancer Research, Montebello, 0310 Oslo, NORWAY.

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Brewer, Bonita J. Department of Genetics, University of Washington, Seattle, WA 98195, USA.

Burgers, Peter M.J. Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Avenue, box 8231, St. Louis, MO 63110, USA.

Burhans, William C. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Campbell, J.L. California Institute of Technology, Divisions of Chemistry and Biology 147-75CH, Pasadena, CA 91125, USA.

Chang, V. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

Christ, C. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

Clertant, Philippe. University of Nice, INSERM U.273, Centre de Biochimie, Parc Valrose, 06034 Nice Cedex, FRANCE.

Collins, Kathleen L. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Damagnez, V. C.N.R.S.-U.P.R.272, Laboratoire de Biologie Moleculaire de la Replication, 94800 Villejuif, FRANCE.

Dasgupta, Santanu. Department of Microbiology, University of Uppsala, The Biomedicale Center, Box 581, S-75123 Uppsala, SWEDEN.

Dawson, A. Department of Biochemistry and Microbiology, University of St. Andrews, St. Andrews, Fife KY169AL. SCOTLAND.

Dehde, Silke. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

DePamphilis, Melvin L. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Derossi, D. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

De Recondo, Anne-Marie. C.N.R.S.-U.P.R.272, Laboratoire de Biologie Moleculaire de la Replication, 94800 Villejuif, FRANCE.

Diaz, Ram6n. Centro de Investigaciones Biologicas, Velazquez 144, 28006 Madrid, SPAIN.

Diffiey, John F.x. Imperial Cancer Research Fund, Clare Hall Laboratories, Blance Lane, South Mimms, Potters Bar, Herts. EN6 3LD, U.K.

Dornreiter, Irene. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

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Dubey, Dharani D. Department of Zoology, Kidir Mahairdyalaya, Chakkey, Jaunpur-222 U.P., INDIA.

Elble, R. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

Engler, Jeffrey A. Department of Biochemistry, University of Alabama at Brimingham, Schools of Medicine and Dentistry, UAB Station, Birmingham, Alabama 35294, USA.

Erdile, Lorne F. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Esteban, J.A. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Fabre, F. Institut Curie-Biologie, Bl1timent 110, Centre Universitaire, 91405 Orsay, FRANCE.

Fanning, Ellen. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

Faye, G. Institut Curie-Biologie, Bl1timent 110, Centre Universitaire, 91405 Orsay, FRANCE.

Fernandez-Tresguerres, Maria Elena. Centro de Investigaciones Biologicas, Velazquez 144, 28006 Madrid, SPAIN.

Foiani, M. Dipartimento di Genetica et di Biologia dei Microrganismi, UniversitA di Milano, Via Celoria 26, 20133 Milano, ITALY.

Francesconi, S. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Fredman, Jeffrey N. Department of Biochemistry, University of Alabama at Brimingham, Schools of Medicine and Dentistry, UAB Station, Birmingham, Alabama 35294, USA.

Freire, R. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Garmendia, C. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Gasser, S.M. Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses, CH-1066 Epalinges/Lausanne, SWITZERLAND.

Georgopoulos, C. Department of Cellular, Viral and Molecular Biology, University of Utah, School of Medicine, Salt Lake City, Utah 84132,USA.

Gibson, S. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

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Gilbert, Ilka. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

Giot, L. Institut Curie-Biologie, Batiment 110, Centre Universitaire, 91405 Orsay, FRANCE.

Giraldo, Rafael. Centro de Investigaciones Biologicas, Velazquez 144, 28006 Madrid, SPAIN.

Guo, Zong-Sheng. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Gutierrez, C. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Hay, Ronald T. Department of Biochemistry and Microbiology, University of St. Andrews, St. Andrews, Fife KY169AL. SCOTLAND.

Hermoso, J.M. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Herrick, John. Institut Jacques Monod, CNRS, Universite Paris 7, 2 place Jussieu, 75251 Paris Cedex 05, FRANCE.

Hofmann, J.F.X. Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses, CH-1066 EpalingeslLausanne, SWITZERLAND.

Holz, Andreas. Max-Planck-Institut fUr Molekulare Genetik, Abt. Trautner, Ihnestrasse 63, D-lOOO Berlin 33, GERMANY.

Horwitz, Marshall S. Department of Microbiology-Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

Hoskins, Joel. Centre for Advanced Research in Biotechnology, National Institute of Standards and Technology, Rockville, MD 20850, USA.

Huberman, Joel A. Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.

Hughes, Patrick. Institut Jacques Monod, CNRS, Universite Paris 7, 2 place Jussieu, 75251 Paris Cedex 05, FRANCE.

Johnson, C. Division of Biophysics, Department of Cellular, Viral and Molecular Biology, University of Utah, School of Medicine, Salt Lake City, Utah 84132,USA.

Joung, Insil. Department of Biochemistry, University of Alabama at Brimingham, Schools of Medicine and Dentistry, UAB Station, Birmingham, Alabama 35294, USA.

Karwan, Anneliese. Department of Molecular Genetics, Institute for Tumorbiology and Cancer Research, University of Vienna, Borschkegasse 8a, 1090 Wien, AUSTRIA.

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Kearsey, Stephen E. Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, U.K.

Kelly, Thomas J. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Kern, Renee. Institut Jacques Monod, CNRS, Universite Paris 7, 2 place Jussieu, 75251 Paris Cedex 05, FRANCE.

Kipling, David. Department of Zoology, University of Oxford, South Parks Road, Oxford, OX13PS, U.K.

Knippers, R. Division of Biology, University of Konstanz, D-7750 Konstanz, FRG.

Kohiyama, Masamichi. Institut Jacques Monod, CNRS, Universite Paris 7, 2 place Jussieu, 75251 Paris Cedex 05, FRANCE.

Kornberg, A. Department of Biochemistry,' Beckman Center, Stanford University, Stanford, CA 94305-5307, USA.

Kunze, N. Division of Biology, University of Konstanz, D-7750 Konstanz, FRG.

Lambrecht, Ch. Division of Biology, University of Konstanz, D-7750 Konstanz, FRG.

Lazaro, J.M. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Liberek, K. Division of Biophysics, Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk, POLAND.

Linskens, Maarten H.K. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.

L~bner-Olesen, Anders. Department of Microbiology, The Technical University of Denmark, 2800 Lyngby, DENMARK.

Locati, F. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Longhese, M.P. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Lucchini, G. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Lyngstadass, Anita. Department of Biophysics, Institute for Cancer Research, Montebello, 0310 Oslo, NORWAY.

Maddock, A. Department of Cellular, Viral and Molecular Biology, University of Utah, School of Medicine, Salt Lake City, Utah 84132,USA.

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Mah, D. McGill Cancer Centre, McGill University, 3655 Drummond Street, Montreal,Quebec H3G IY6, CANADA.

Majumder, Sadhan. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Malki, Abderrahim. Institut Jacques Monod, CNRS, Universite Paris 7, 2 place Jussieu, 75251 Paris Cedex 05, FRANCE.

Marszalek, J. Division of Biophysics, Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk, POLAND.

Martin, Margarita. Centro de Investigaciones Biologicas, Velazquez 144, 28006 Madrid, SPAIN.

McAlear, M. McGill Cancer Centre, McGill University, 3655 Drummond Street, Montreal,Quebec H3G IY6, CANADA.

McKenney, Keith. Centre for Advanced Research in Biotechnology, National Institute of Standards and Technology, Rockville, MD 20850, USA.

Mendez, J. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Messer, Walter. Max-Planck-Institut fur Molekulare Genetik, Abt. Trautner, Ihnestrasse 63, D-1000 Berlin 33, GERMANY.

Miranda, Miriam. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Moriya, S. Department of Genetics, Osaka University Medical School, 2-2, Yamadaoka, Suita 565, JAPAN.

Mul, Y.M. Laboratory for Physiological Chemistry, University of Utrecht, Vondellaan 24a, 3521 GG Utrecht, THE NETHERLANDS.

Muzi Falconi, M. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Nallaseth, Ferez S. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Nasheuer, Heinz-Peter. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

Nawotka, Kevin A. Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.

Newlon, Carol S. Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, N.J. 07103, USA.

Nieto, Concepcion. Centro de Investigaciones Biologicas, Velazquez 144, 28006 Madrid, SPAIN.

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Nordstrom, Kurt. Department of Microbiology, University of Uppsala, The Biomedical Center, Box 581, S-75123 Uppsala, SWEDEN.

Nurse, Paul. ICRF Cell Cycle Group, Microbiology Unit, Department of Biochemistry, University of Oxfor, South Parks Road, Oxford OXI 3QU, U.K.

Ogasawara, N. Department of Genetics, Osaka University Medical School, 2-2, Yamadaoka, Suita 565, JAPAN.

Opisiuk, J. Division of Biophysics, Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk, POLAND.

Passmore, S. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

Pearson, C.E. McGill Cancer Centre, McGill University, 3655 Drummond Street, Montreal,Quebec H3G lY6, CANADA.

Pettit, Steven C. Department of Biochemistry, University of Alabama at Brimingham, Schools of Medicine and Dentistry, UAB Station, Birmingham, Alabama 35294, USA.

Piatti, S. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Pignede, G. C.N.R.S.-U.P.R.272, Laboratoire de Biologie Moleculaire de la Replication, 94800 Villejuif, FRANCE.

Piseri, A. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Pizzagalli, A. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Plevani, P. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26, 20133 Milano, ITALY.

Price, G.B. McGill Cancer Centre, McGill University, 3655 Drummond Street, Montreal,Quebec H3G lY6, CANADA.

Randall, Sandra K. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Rhode, P.R. California Institute of Technology, Divisions of Chemistry and Biology 147-75CH, Pasadena, CA 91125, USA.

Richter, A. Division of Biology, University of Konstanz, D-7750 Konstanz, FRG.

Romig, H. Division of Biology, University of Konstanz, D-7750 Konstanz, FRG.

Russev, George. Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia 1113, BULGARIA.

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Russo, Alicia A.R.. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Salas, M. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Sanchez, J. Aquiles. Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.

Santocanale, C. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26,20133 Milano, ITALY.

Santucci, Sabine. University of Nice, INSERM U.273, Centre de Biochimie, Parc Valrose, 06034 Nice Cedex, FRANCE.

Schaefer, Christoph. Max-Planck-Institut fur Molekulare Genetik, Abt. Trautner, Ihnestrasse 63, D-I000 Berlin 33, GERMANY.

Schneider, Christine. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

Serrano, M. Centro de Biologia Molecular (CSIC-UAM), Universidad Autonoma, Canto Blanco, 28049 Madrid, SPAIN.

Simancek, Pamela R. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Simon, M. Institut Curie-Biologie, Bdtiment 110, Centre Universitaire, 91405 Orsay, FRANCE.

Skowyra, D. Division of Biophysics, Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk, POLAND.

Sogo, Jose M. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Stillman, Bruce. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.

Tazzi, R. Dipartimento di Genetica et di Biologia dei Microrganismi, Universita di Milano, Via Celoria 26,20133 Milano, ITALY.

Temperley, S.M. Department of Biochemistry and Microbiology, University of St. Andrews, St. Andrews, Fife KY169AL. SCOTLAND.

Theis, James F. Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, N.J. 07103, USA.

Tye, B.K. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

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Umbricht, Christopher B. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Van der Vliet, P.C. Laboratory for Physiological Chemistry, University of Utrecht, Vondellaan 24a, 3521 GG Utrecht, THE NETHERLANDS.

Van Driel, W. Laboratory for Physiological Chemistry, University of Utrecht, Vondellaan 24a, 3521 GG Utrecht, THE NETHERLANDS.

Van Oosterhout, J.A.W.M. Laboratory for Physiological Chemistry, University of Utrecht, Vondellaan 24a, 3521 GG Utrecht, THE NETHERLANDS.

Vassal, A. Institut Curie-Biologie, Biitiment 110, Centre Universitaire, 91405 Orsay, FRANCE.

Vassilev, Lyubomir T. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Verrijzer, C.P. Laboratory for Physiological Chemistry, University of Utrecht, Vondellaan 24a, 3521 GG Utrecht, THE NETHERLANDS.

Virshup, David M. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Von Winkler, Dorothea. Institute for Biochemistry, Karlstrasse 23, 8000 Munich 2, FEDERAL REPUBLIC OF GERMANY.

Wang, S.S. Fred Hutchinson Cancer Research Center, 1124 Columbia St, Seattle, WA 98104, USA.

Weinberg, David H. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Wellinger, R. Fred Hutchinson Cancer Research Center, 1124 Columbia St, Seattle, WA 98104, USA.

Wickner, Sue. Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Wiekowski, Maria. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

Wintersberger, Ulrike. Department of Molecular Genetics, Institute for Tumorbiology and Cancer Research, University of Vienna, Borschkegasse 8a, 1090 Wien, AUSTRIA.

Wold, Marc S. Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

Wu, Jiarui. Department of Cell and Developmental Biology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA.

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Yan, H. Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.

Yoon, Yeup. Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.

Yoshikawa, H. Department of Genetics, Osaka University Medical School, 2-2, Yamadaoka, Suita 565, JAPAN.

Zakian, V.A. Fred Hutchinson Cancer Research Center, 1124 Columbia St, Seattle, WA 98104, USA.

Zannis-Hadjopoulos, M. McGill Cancer Centre, McGill University, 3655 Drummond Street, Montreal,Quebec H3G IY6, CANADA.

Zylicz, M. Division of Biophysics, Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk, POLAND.