MolecularBiologyof Fifth Edition
MolecularBiologyof Fifth Edition
BruceAlberts Johnson Alexander JulianLewis MartinRaff KeithRoberts PeterWalter
Withproblemsby JohnWilson TimHunt
GarlandScience Group Taylor& Francis
Garland Science Vice President:Denise Schanck Assistant Editor: Sigrid Masson Production Editor and Layout: Emma leffcock Senior Publisher: Jackie Harbor Illustrator: Nigel Orme Designer: Matthew McClements, Blink Studio, Ltc. Editors: Marjorie Anderson and Sherry Granum Copy Editor: Bruce Goatly Indexer: Merrall-Ross International, Ltd. Permissions Coordinator: Marv Disoenza Cell Biology Interactiue Artistic and Scientific Direction: PeterWalter Narrated by: Julie Theriot Production Design and Development: Michael Morales
@ 2008, 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Rafi Keith Roberts, and PeterWalter. @ f 983, f 989, 1994 by Bruce Alberts, Dennis Bray, Iulian Lewis, Martin Raff, Keith Roberts, and lames D. Watson.
Bruce Alberts received his Ph.D. from Harvard university and is professor of Biochemistry and Biophysics at the university of california, san Francisco.For 12 years,he served as President ofthe u.s. NationalAcademy ofSciences (1993-2005). Alexander Johnson received his Ph.D. from Harvard University and is professor of Microbiology and Immunology and Director of the Biochemistry cell Biology, Genetics, and Developmental Biology Graduate Program at the University of california, San Francisco. Iulian Lewis received his D.Phil. from the University of Oxford and is a Principal Scientist at the London ResearchInstitute of Cancer ResearchUK. Martin Raffreceived his M.D. from McGill University and is at the Medical Research Council Laboratory for Molecular Cell Biology and the Biology Department at University College London. Keith Roberts received his Ph.D. from the University of Cambridge and is Emeritus Fellow at the John Innes Centre, Norwich. peterWalter received his ph.D. from The Rockefeller University in Newyork and is professor and chairman of the Department of Biochemistry and Biophysics at the University of california, san Francisco, and an Investigator of the Howard Hughes Medical Institute.
All rights reserved. No part of this book covered by the copyright heron may be reproduced or used in any format in any form or by any means-graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems-without permission of the publisher. Library of CongressCataloging-in-Publication Data Molecularbiology of the cell / BruceAlberts ... [et al.].-- 5th ed. p.cm ISBN 978-0-8153-4r05-5 (hardcover)---ISBN978-0-8f5 g-4t06_Z(paperback) L Cytology.2. Molecular biology. I. Alberts, Bruce. QHsB1.2.M642008 571.6--dc22 2007005475CIP Published by Garland science, Taylor & Francis Group, LLC, an informa business, 270 Madison Avenue, NewYork NY f 0016,USA, and 2 park Square,Milton park, Abingdon, OXl4 4RN, UK. Printed in the United States of America 15 14 13 12 lt
B 7 6 5 4 3 2 |
Preface In many respects,we understand the structure of the universebetter than the workings of living cells.Scientistscan calculatethe age of the Sun and predict when it will ceaseto shine,but we cannot explain how it is that a human being may live for eighty years but a mouse for only two. We know the complete genomesequencesof theseand many other species,but we still cannot predict how a cell will behaveif we mutate a previouslyunstudied gene.Starsmay be l0a3times bigger,but cells are more complex, more intricately structured,and more astonishingproductsof the laws of physicsand chemistry.Through heredity and natural selection,operating from the beginningsof life on Earth to the presentday-that is, for about 20Voof the ageof the universe-living cellshave been progressivelyrefining and extending their molecular machinery and recording the results of their experimentsin the genetic instructions they pass on to their progeny. With each edition of this book, we marvel at the new information that cell biologistshave gatheredin just a few years.But we are even more amazedand daunted at the sophisticationof the mechanismsthat we encounter.The deeper we probe into the cell,the more we reafizehow much remainsto be understood. In the daysof our innocence,working on the first edition, we hailed the identification of a singleprotein-a signalreceptol say-as a greatstep forward' Now we appreciatethat eachprotein is generallypart of a complexwith many others, working togetheras a system,regulatingone another'sactivitiesin subtleways, and held in specificpositionsby binding to scaffoldproteins that givethe chemical factory a definite spatial structure.Genomesequencinghas given us virtually complete molecular parts-listsfor many different organisms;geneticsand biochemistry have told us a great deal about what those parts are capableof individually and which ones interact with which others; but we have only the most primitive grasp of the dynamics of these biochemical systems,with all their interlocking control loops. Therefore,although there are great achievements to report, cell biologistsface evengreaterchallengesfor the future. In this edition, we haveincluded new material on many topics,rangingfrom epigenetics,histonemodifications,small RNAs,and comparativegenomics,to geneticnoise,cytoskeletaldlmamics,cell-cyclecontrol, apoptosis,stem cells, and novel cancer therapies.As in previous editions, we have tried aboveall to give readersa conceptualframework for the mass of information that we now have about cells.This meansgoing beyond the recitation of facts.The goal is to learn how to put the facts to use-to reason,to predict, and to control the behavior of living systems. To help readerson the way to an activeunderstanding,we have for the first time incorporatedend-of-chapterproblems,written by Iohn Wilson and Tim Hunt. Theseemphasizea quantitative approach and the art of reasoningfrom experiments.A companion volume, MolecularBiologyof the CelI,Fifth Edition: by the sameauthors,givescomTheProblemsBook0SBN978-0-8153-4110-9), plete answersto theseproblemsand also containsmore than 1700additional problemsand solutions. A further major adjunct to the main book is the attachedMedia DVD-ROM disc.This provideshundredsof moviesand animations,including manythat are new in this edition, showingcells and cellular processesin action and bringing the text to life; the disc alsonow includesall the figuresand tablesfrom the main
book,pre-loadedinto [email protected]
presentations. Otherancillariesavailablefor the book include a bank of test questionsand lectureoutlines,availableto qualified instructors,and a set of 200full-coloroverheadtransparencies. Perhapsthe biggestchange is in the physical structure of the book. In an effort to make the standard Student Edition somewhatmore portable, we are providing chapters 2r-25, covering multicellular systems,in electronic (pDF) form on the accompanyingdisc,while retaining in the printed volume chapters l-20, covering the core of the usual cell biology curriculum. But we should emphasizethat the final chaptershavebeen revisedand updated as thoroughly as the rest of the book and we sincerelyhope that they will be read!A Reference Edition (ISBN97s-0-8153-4r11-6), containingthe full set of chaptersasprinred pages,is also availablefor thosewho prefer it. Full details of the conventionsadopted in the book are given in the Note to the Readerthat follows this Preface.As explainedthere,we have taken a drastic approachin confronting the different rules for the writing of genenamesin different species:throughout this book, we use the same style, regardlessof species,and often in defianceofthe usualspecies-specific conventions. As always,we are indebted to many people. Full acknowledgmentsfor scientific help are given separately,but we must here singleout someexceptionally important contributions: Iulie Theriot is almost entirely responsiblefor chapters 16 (cytoskeleton)and 24 (Pathogens,Infection, and Innate Immunity), and David Morgan likewisefor chapter 17 (cell cycle).wallace Marshall and Laura Attardi provided substantialhelp with chapters 8 and 20, respectively,as did Maynardolson for the genomicssectionof chapter4, Xiaodongwangfor chapter 18,and NicholasHarberdfor the plant sectionof Chapter15. we also owe a huge debt to the staff of Garland science and others who helped convert writers' efforts into a polished final product. Denise schanck directed the whole enterpriseand shepherdedthe wayward authors along the road with wisdom, skill, and kindness.Nigel orme put the artwork into its final form and supervisedthe visualaspectsof the book,including the backcover,with his usual flair. Matthew Mcclements designedthe book and its front cover. Emma Jeffcocklaid out its pageswith extraordinaryspeedand unflappableefficiency,dealingimpeccablywith innumerablecorrections.MichaelMoralesmanagedthe transformationof a massof animations,video clips, and other materials into a user-friendly DVD-ROM. Eleanor Lawrence and sherry Granum updatedand enlargedthe glossary.JackieHarbor and SigridMassonkept us organized.Adam Sendroffkeptus awareofour readersand their needsand reactions. MarjorieAnderson,BruceGoatly,and sherry Granumcombedthe text for obscurities, infelicities, and errors.we thank them all, not only for their professional skill and dedication and for efficiencyfar surpassingour own, but also for their unfailing helpftrlnessand friendship:they havemadeit a pleasureto work on the book. Lastly,and with no less gratitude, we thank our spouses,families, friends and colleagues. without their patient,enduringsupport,we could not haveproducedany of the editionsof this book.
Contents Speci.al Features Detailed Contents Acknowledgments A Note to the Reader
uiii ix xxui xxxi
I. 2. 3.
TOTHECELL INTRODUCTION Cellsand Genomes CellChemistryand Biosynthesis Proteins
I 45 t25
PARTII 4. 5. 6. 7.
MECHANISMS BASICGENETIC DNA, Chromosomes,and...