MEDICAL INTELLIGENCE UNIT Molecular Mechanisms of Fanconi Anemia Shamim I. Ahmad, B.Sc, M.Sc, Ph.D. School of Biomedical and Natural Sciences Nottingham Trent University Nottingham, England, U.K. Sandra H. Kirk, B.Sc. (Hons.), Ph.D. School of Biomedical and Natural Sciences Nottingham Trent University Nottingham, England, U.K. LANDES BIOSCIENCE / EUREKAH.COM SPRINGER SCIENCE+BUSINESS MEDIA GEORGETOWN, TEXAS NEW YORK, NEW YORK U.S.A. U.S.A. MOLECULAR MECHANISMS OF FANCONI ANEMIA Medical Intelligence Unit Landes Bioscience / Eurekah.com Springer Science+Business Media, Inc. ISBN: 0-387-31972-7 Printed on acid-free paper. Copyright ©2006 Eurekah.com and Springer Science+Business Media, Inc. All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher, except for brief excerpts in connection with reviews or scholarly analysis. 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In view of the ongoing research, equipment development, changes in governmental r^;ulations and the rapid accumulation of information relating to the biomedical sciences, the reader is urged to carefiiUy review and evaluate the information provided herein. Springer Science+Business Media, Inc., 233 Spring Street, New York, New York 10013, U.S.A. http://www.springer.com Please address all inquiries to the Publishers: Landes Bioscience / Eurekah.com, 810 South Church Street, Georgetown, Texas 78626, U.S.A. Phone: 512/ 863 7762; FAX: 512/ 863 0081 http://www.eurekah.com http://www.landesbioscience.com Printed in the United States of America. 9 8 7 6 5 4 3 21 Library of Congress Cataloging-in-Publication Data Molecular mechanisms of Fanconi anemia / [edited by] Shamim I. Ahmad, Sandra H. Kirk, p. ; cm. ~ (Molecular biology intelligence unit) Includes bibliographical references and index. ISBN 0-387-31972-7 (alk paper) 1. Fanconi's anemia—Genetic aspects. 2. Fanconi's anemia—Molecular aspects. I. Ahmad, Shamim I. II. Kirk, Sandra H. III. Title. IV. Series: Molecular biology intelligence unit (Unnumbered) [DNLM: 1. Fanconi Anemia-genetics. WH 175 M718 2006] RC641.7.F36M65 2006 6l6.1'52071-dc22 2005037313 CONTENTS Preface vii 1. Clinical Features of Fanconi Anaemia 1 A. Malcolm R. Taylor Genetics of Fanconi Anaemia 2 Clinical Features of Fanconi Anaemia 3 Fanconi Anaemia and Nijmegen Breakage Syndrome 5 Confirmation of the Diagnosis in FA Patients 6 Relationship of Complementation Group to Clinical Features 7 Evidence for Modifying Mutations 10 2. The Genetic Basis of Fanconi Anemia 13 Grover C. Bagby, Jr. Genetic Heterogeneity 13 The iMA^C Genes 14 FA Protein Complexes 21 3. The FANCA Gene and Its Products 28 Laura S. Haneline FANCAGenc 28 FANCA Protein 29 FANCA Function 30 Acquired AML and FANCA Defects 32 4. The FANCC Gene and Its Products 36 Susan M. Gordon and Manuel Buchwald Cloning and Characteristics of the FANCC Gene 36 Mammalian Homologs of FANCC 37 FANCC Gene Mutations 39 Expression of the FANCC Gene Products 40 FANCC Protein Expression and Stability 41 FANCC Subcellular Localization 41 FANCC in the Cellular Response to ICL Inducers 42 Apoptosis 43 FANCCLoss of Function 43 FANCC and Cytokine Signalling 45 FANCC and Oxidative Stress 47 5. The FANCB, E, Fand G Genes and Their Products 54 Filippo Rosselli FANCB 55 FANCC 56 FANCF 57 FANCE 57 6. FANCD1/BRCA2 and FANCD2 61 Gary M. Kupfer The FA-D Complementation Group 61 7. The FANC Genome Surveillance Complex 67 Takayuki Yamashita Historical Overview 67 Structure of the FA Core Complex 69 Functions of the FA Core Complex 70 Perspectives 71 8. Other Proteins and Their Interactions with FA Gene Products 74 Tetsuya Otsuki and Johnson M. Liu FANCC-Binding Proteins 7A FANCA-Binding Proteins 75 FA Protein Complex and Human a Spectrin II 78 9. Fanconi Anaemia and Oxidative Stress: Cellular and Clinical Phenotypes 82 Giovanni Pagano and Shamim I. Ahmad 10. Therapy for Fanconi Anemia 92 Madeleine Carreau Androgens 92 Hematopoietic Growth Factors 92 BM Transplants 93 Gene Therapy 96 Prospects for Therapy 98 11. Mutational Analyses of Fanconi Anemia Genes in Japanese Patients 103 Akira Tachibana Patients, Cell Culture and Mutation Analysis 103 Sequence Variations in the FANCA Gene 104 Sequence Variations in the FANCG Gene 108 Mutations of the ir^4A^CC Gene Ill Mutations of Other FA Genes Ill Characteristics and Genetic Basis of Japanese FA Patients Ill Index 115 EDITORS Shamim I. Ahmad School of Biomedical and Natural Sciences Nottingham Trent University Nottingham, England, U.K. Email: [email protected] Preface, Chapter 9 Sandra H. Kirk School of Biomedical and Natural Sciences Nottingham Trent University Nottingham, England, U.K. Email: [email protected] Preface CONTRIBUTORS Grover C. B^by, Jr. Susan M. Gordon OHSU Cancer Institute Program in Genetics Departments of Medicine and Genomic Biology and Molecular and Medical Genetics Research Institute Oregon Health and Science University Hospital for Sick Children Portland, Oregon, U.S.A. Toronto, Ontario, Canada Email: [email protected] Email: [email protected] Chapter 2 Chapter 4 Manuel Buchwald Fumio Hanaoka Department of Molecular Graduate School of Frontier Biosciences and Medical Genetics SORST University of Toronto Japan Science and Technology Toronto, Ontario, Canada Corporation Chapter 4 Suita, Osaka, Japan Preface Madeleine Carreau Department Pediatrie Laura S. Haneline Universite Laval Department of Pediatrics Unite de Recherche en Genetique Herman B. Wells Center Humaine et Moleculaire for Pediatric Research CHUQ, Pavilion St-Francois d'Assise Indianapolis, Indiana, U.S.A. Quebec, Quebec, Canada Email: [email protected] Email: [email protected] Chapter 3 Chapter 10 Gary M. Kupfer Filippo Rosselli Department of Microbiology Laboratory of Genetic Stability Department of Pediatrics and Cancer Division of Pediatric UPR2169,CNRS Hematology-Oncology Gustave Roussy Institute PR2 University of Virginia Villejuif, France Charlottesville, Virginia, U.S.A. Email: [email protected] Email: [email protected] Chapter 5 Chapter 6 Akira Tachibana Johnson M. Liu Radiation Biology Center Schneider Children's Hospital Kyoto University Pediatric Hematology/Oncology Kyoto, Japan and Stem Cell Transplantation Email: New Hyde Park, New York, U.S.A. [email protected]_u.ac.jp Email: [email protected] Chapter 11 Chapter 8 A. Malcolm R. Taylor Tetsuya Otsuki CR-UK Institute for Cancer Studies Clinical Science Planning University of Birmingham and Development Birmingham, England, U.K. Banyu (Merck-Japan) Pharmaceutical Email: [email protected] Company Chapter 1 Tokyo, Japan Email: [email protected] Takayuki Yamashita Chapter 8 Division of Genetic Diagnosis Institute of Medical Science Giovanni Pagano University of Tokyo Centre for Research Tokyo, Japan Innovation and Technology Transfer Email: [email protected] in Oncology and Life Sciences Chapter 7 Mercogliano (AV), Italy Email: [email protected] Chapter 9 PREFACE Fanconi anemia (FA) is a rare largely autosomal recessive genetic disor der (one complementation group being X-linked) that was first recognized almost 40 years ago^ as a cause of juvenile leukemia. Other phenotypes in clude bone marrow failure leading to aplastic anemia, growth retardation, congenital malformations of renal, cardiac, skeletal and skin structures, pan cytopenia and pronounced cancer predisposition. Interestingly FA shares a number of clinical and molecular features with a variety of other syndromes, including Seckel syndrome^ and Nijmegen breakage syndrome,^ and fiirther investigation of all three conditions will provide insights into the molecular mechanisms involved in each one and where they may interact. In the recent past much effort has gone into understanding the mo lecular pathogenesis of FA in terms of enhanced susceptibility to DNA dam aging agents. Results of these studies have yielded exciting information on a multiplicity of hitherto unknown protein-protein interactions involved in activities from control of redox state and apoptosis to repair of DNA strand breaks. ^^ Working with the leading researchers and clinicians in the field, this book has been produced to provide a comprehensive treatise on FA. This covers in detail what is known of the 12 complementation groups identified to date. These include FANCA, -B (X-linked, localized at Xp22.31),'' -C, -Dl, -D2, -E, -F, -G, -I, -J, -L and M. There is clear variation in the clinical features exhibited by sufferers in different complementation groups, and even between those with different mutations of the same gene. This is explored in detail in Chapter 1 and expanded upon in the introduction to Chapter 5. The link between muta tion and phenotype may ultimately help pick apart the complex cellular actions of the FANC proteins. At the other end of the spectrum and the book, Chapter 10 details the best treatments as currently perceived for FA. Whilst the future holds out the possibility of gene therapy or protein re placement, the treatment of choice at present is still stem cell or bone mar row transplantation from a matched sibling.^'^ Chapter 3 introduces the FANC genes identified to date and their prod ucts. It is apparent that FANCA, -B,-C,-E, -F, -G and -L form a core com plex within the nucleus of cells leading to monoubiquitination of FANCD2. ATR checkpoint kinase and RPAl are required for efficient FANCD2 monoubiquitination.^ The nature and roles of this complex are the subjects of Chapter 7. FANCDl and FANCJ appear to act downstream, being ac tively recruited along with BRCAl and RAD51 to chromatin at specific foci for the repair of DNA damage. The precise role of FANCI has not yet been determined but it seems to act at a stage between core complex formation and FANCD2 ubiquitination.^^ The involvement of breast cancer susceptibility and FA genes in this pathway is an area of active research. It is evident that FA-D1 patients are predisposed to breast cancer/^ although members of the other FA complementation groups do not show a high frequency of this malignancy. ^^ This would seem to indicate that the BRCA proteins may exert their breast cancer preventative function independently of FANCD2 ubiquitination (although see below). BRCAl and BRCA2 are known to be independently involved in other activities including regulation of differentiation, and it may be that the disruption of these impacts on breast cancer development.^ In addition to their central role in DNA repair the FA proteins are inti mately involved in a range of other cellular functions through their individual interactions with other proteins. This concept is introduced in Chapter 2 where proteins interacting with FANCA, FANCC and FANCG are introduced. Several of these interactions are with proteins involved in maintenance of redox balance. In Chapter 9, Pagano and Ahmad, long term proponents of the oxidative stress theory of FA, expand upon the ways in which interruptions in FA-redox protein associations could result in the phenotypic abnormalities observed in FA, provid ing an alternative model to the more widely accepted DNA repair deficiency. Abnormalities in mitochondrial function in FA further support a role of oxidative stress."^ It is likely that it is a combination of a deficiency in redox control and ineffective DNA repair which give the complex clinical characteristics of this dis order: many of the congenital abnormalities arising due to the former, and predis position to malignancy to the latter. It is highly probable, however, that the debate over the relative contributions of these two phenomena will continue for some time. Mutations in FANCA, -C and -G are the most prevalent and the individual genes and their products are considered in detail in Chapters 3-5. Interestingly other proteins which FANCA, -C and -G interact with are known or suggested to be involved in chromatin remodeling (e.g., FAZF^^ and BRGl),^^ and FANCC in particular appears to have a role in protection against cytokine-induced apoptosis in haematopoietic cells. These phenomena are discussed in detail in Chapters 4 and 8 and evidence is beginning to appear to suggest that different structural domain within FANCC are responsible for its different activities. FANCG con tains sequence motifs typical of a protein involved in protein-protein interactions, and it is essential for the functional interaction between FANCC and FANCA. In turn its ability to interact with FANCA requires the presence of FANCB, -C and -F, illustrating further the intricate interplay of these proteins which is explored in detail in Chapter 5. Chapter 6 considers the natures of FANCDl and -D2 proteins. The excit ing discovery that FANCDl is in fact the breast cancer susceptibility gene product BRCA2, and that ubiquitinated FANCD2 interacts with BRCAl have hugely expanded the research efforts in this area. The nuclear FA complex appears to exert its effects in a two pronged approach: by ubiquitination of FANCD2 which in turn recruits BRCAl to the nuclear foci formed at DNA repair sites, and via interactions (possibly through FANCG association) with BRCA2 and RAD51, these proteins also being recruited to damage foci although seemingly indepen dently of BRCAl.^^ The detail of these interactions and their roles in damage repair are under intense investigation, particularly as BRCAl recruitment seems to be implicated in a range of DNA repair mechanisms. ^^ The final chapter (Chapter 12) is devoted to an in depth discussion of the mutations found in a geographically and genetically isolated Japanese FA popula tion. Interestingly this group shows a preponderance of mutations in FANCA as is observed in the West, but also shows a higher frequency of FANCG involvement, confirming the central role of FANCA and the FANCA-FANCC-FANCG com plex in protection against FA. A recent Tunisian study of 41 families has revealed that 92% belong to the FANCA complementation group.^ Others have identified Spanish Gypsies as the ethnic group with the world s highest prevalence of FA—the carrier frequency being 1/64-1/70.^ Affected individuals are homozygous for a specific FANCA mutation (295C>T) leading to FANCA truncation. This mutation was not found in other Gypsy patients from Hungary, Germany, Slovakia and Ireland. In a South ern African population (South Africa, Swaziland, Mozambique and Malawi) a particular deletion mutation in FANCG (c.637 643delTAACCGCC) has been reported in 82% of FA patients. Birth incidence of FA in this population is greater than 1/40,000 which is above average in general populations. These studies are clearly indicative of founder mutation in the Spanish gypsy and Southern African populations. There is no evidence that interest in FA is waning, and this book should provide both the experts and novice researchers in the field with an excellent over view of the current status of research and pointers to fixture research goals. Note Added in Proof In a recent study Meetei et al have identified a new complementation group, FANCM. The protein, FAAp250, is a part of the FA protein complex involving BRCAl and BRCA2 and has sequence similarity to other known DNA repair proteins, including Hef in archaea, MPHl in yeast and ERCC4 or XPF in hu man. FANCM is essential for monoubiquitination of FANCD2 and is hyperphosphorylated when DNA is damaged. Shamim L Ahmady Futnio Hanaoka and Sandra H. Kirk