Unlocking the Secrets of Eukaryotic Nuclei Functional Organization of the Nucleus: A Laboratoly Guide (1991). Edited by B. HAMKALO AND S. R. ELGTN. Academic Press, San Diego. pp. 670. $95, hc; $49.95 pb.

By Dean Jackson With all the hype that has accompanied international initia- tives to sequence the human genome, over the past year or so, one could be forgiven for imagining that the complete sequence will reveal most, perhaps all, of the genome’s secrets. I, like many observers, believe this is unlikely and wonder to what extent this initiative will be outwitted by intricacies that undoubtedly influence gene expression in vivo. This view is not unprecedented as features of nuclear organization that were, when first identified, quite unex- pected are not hard to find: genes in pieces, permitting prod- uct variability by alternative splicing; huge distances (up to 100 kb) separating coding sequences and important control motifs; highly structured replication centers and structured routes for hnRNA processing and transport, these are just a few that spring to mind. I anticipate that only by understand- ing the details of nuclear organization will we at last hold the key to unlock the secrets of the eukaryotic nucleus.

The appearance of Functional Organization of the Nucleus: A Laboratory Guide is, without doubt, timely. As different aspects of organization find their way into the spot- light, this volume, presenting a collection of articles which give the reader a detailed insight into appropriate experimen- tal options, is particularly valuable. This book is presented as a laboratory manual and while it sports the appropriate flexy plastic spine I wonder to what extent this is a marketing ploy, devised by the publishers. Cynical perhaps, but to be fair this format does yield a product that is likely to be more durable than alternative sources of related research articles, typically conference proceedings.

What about the content? No prizes for guessing that an enormous amount of ground is covered. The set out is as follows: i) 5 chapters on nucleic acid hybridization covering DNA sequences in cell and chromosome preparations and the localization of hnFWA and mRNA in situ. Most employ the more accessible (i.e. technically less demanding) fluores- cence-based technology, one chapter describes how electron microscopy can be used; ii) the second section covers the use of antibodies to study nuclear and chromosome organization. Excellent chapters cover classical indirect immunofluores- cence techniques. The use of monoclonal libraries to screen and characterise different nuclcar components is followed by a remarkably clear description of the use of optical section- ing for 3D nuclear reconstruction; iii) the next section begins to approach details of molecular intricacies that underlic nuclear structure and function. Three chapters focus on chro- matin, describing the analysis of nucleosome disposition and explaining how the characteristics of active and inactive chromatin can be used for gene fractionation. Two methods for assessing the location of non-histone proteins, in vivo, are described; iv) 3 chapters on functional complexes and their reconstruction cover factors that influence gene expression during nucleosome assembly, general features of assembly

ISBN 012-321920

using components from Xenopus laevis egg extracts and nuclear transport; and finally, section v) describes how genetics can be used to dissect different aspects of nuclear structure and function in yeast and Drosophila.

My overall impression of individual chapters was, in gen- eral, extremely favourable. Very few were disappointing and many, I found, especially valuable for their depth of detail. The first chapter, for example, is a model in this respect, pre- senting each section with a brief but decisive introduction and then clearly defined protocols, including details which are crucial yet, all to often, ill-defined in original reaearch articles. And all the more remarkable for presenting detailed protocols in a reasonably palatable form. When the same for- mat was not maintained throughout, I was not entirely sur- prised; a minority of chapters seemed more reminiscent of typical research reviews. Perhaps not a serious concern, and one that might be overlooked in deference to obtaining con- tributions from the best possible sources. On the down side, this type of compilation can also cause problems. For exam- ple, a top quality laboratory manual should assess alterna- tives and provide advice as to which protocols are appropri- ate/preferable in different situations. Here, each chapter presents its own package and the reader gets no particular feel as to which approaches might best achieve a certain goal. For example, a large part of this work uses fluorescence microscopy but the need for, and relative merits of, different analytical systems - simple microscopy, confocal systems or CCD-based systems - does not come over clearly.

The theme of this volume undoubtedly covers a lot of terri- tory. Many contributions demand automatic selection but, almost inevitably (given editorial preference), others seem ill-placed. Not in itself so irritating as some apparent omis- sions. For example, not a single chapter looks directly at the most familiar nuclear functions - transcription and replica- tion - i n somatic cells or nuclei isolated from them. Quite a flaw, you might imagine, in a volume dedicated to functional organization in the nucleus. Even worse, as work analyzing the organizing of replication centres provided, in my view, the single most important contribution relating to this theme. Ifincluded, this might at least have disguised the almost bla- tant disregard of relevant work on the nuclear matrix. Gene activation might also be considered central to this theme, and might reasonably warrant more attention. Perhaps the editors believe this area has received adequate attention, of late; if so I’m inclined to agree but for the sake of completeness some discussion of long-range organizational features, such as ele- ments that appear to be responsible for chromatin domain formation or remote control sequences, such as the globin LCRs, might seem wiell placed. Other omissions on my list look less important, more a matter of personal preference and no real surprise - all of us who have lived with such a com- plex and wide ranging field for any length of time inevitably developed our own, rather personalized, perspective.

I doubt if this type of compilation could ever appeal to the sensitivities of each specialist working in the appropriate area. Clearly this is not the point. This volume, despite my apparent criticism, provides a reasonably well balanced account of most aspects of nuclear structure and, where

appropriate, gives valuable pointers as to how structure and function might be related. As a laboratory guide this \iolume is bound to present an experimental bias. Happily most con- tributions achicve this and, at the same time, give just enough detail of original research to make them a worthwhile source for reference - even though the laboratory manual format severley restricts data presentation (only 2 or 3 original fig- ures are presented in most chapters) - and reasonably enjoy- able read. I have no doubt that the quality of experimental detail presented in this volume more than justifies its exis- tence. I would happily recommend it as a technical guide to specialists working in the many related areas who feel they might like to broaden their honzons. In addition, and perhaps more importantly, I believe this volume provides anyone new to this area with an invaluable overview of a complex field. Selling at only E30 this volume is a must for appropri- ate Departmental libraries. Even personal purchases could turn out to be money well spent.

Dean Jackson, Sir William Dunn School of Pathology, ~

University of Oxford, South Parks Road, Oxford OX1 I 3RE.

‘Living Test-tubes’, Eyebrow Knives, and Almost Living Extracts Methods in Cell Biology vol36. Xenopus laevis: Pructicul Uses in Cell undMoZecL(lurBio1ogy (1991). Edited by B. K. KAY AND H. B. PENG. Academic Press San Diego. pp. xxii+718. $1 15.0OE72. ISBN 0-12-564136-2. By Chris Ford Xenopus initially colonized laboratory environments through its capacity to lay eggs in response to injections of human chorionic gonadotrophin. Subsequently, through its easy- going aquatic lifestyle, fecundity and the accessibility of its large embryos, it has expanded its international range to lab- oratories of cell, molecular and developmental biologists. Early developmental stages of Xenopus are primarily ana- lyzed in their own right as a particular developing system, but also are used as assay system for gene expression following injection into the ‘living test-tube’. The thirty two chapters of this volume of Methods in Cell Biology attest to the diversity of issues that can be addresqed with this system.

The chapters are grouped under four headings: general information, oocytes, embryos and model systems. In addition there are a series of appendices providing technical details not explicitly covered elsewhere and including a modified wholemount procedure. Essentially all of the chap- ters contain background information on the biological prob- lems for which the techniques were originally developed, as well as (usually) detailed protocols and examples of the sorts

of results that have been obtained. In many places there is consideration of the importance of particular steps and com- parison of the advantages and limitations of related proce- dures. What can go wrong, and what has been tried without success, are also considered in some cases. Overall the pre- sentation is far more than a manual of methods.

Under general information are chapters on maintenance and rearing of Xenopus, genetics and induction of homozy- gosity, oogenesis and embryogenesis. Even though Xenopus is not fastidious in its requirements for living and breeding, oocyte and egg quality are crucially important for all types of experimental analysis and depend on the health and well being of the adults. Seasonal variability is annoying, but for- tunately the period of reduced quality is short. To all intents and purposes good oocytes and eggs can be obtained on demand, even without regular exposure of animals to Han- del’s Water Music!

Parts 2 and 3 deal with a variety of procedures developed to tackle molecular and developmental questions of oogene- sis and embryogenesis in Xennpus. Oocytes can be cultured, matured and then fertilized in vitro, making the role of inter- nal components in the earliest events after fertilization unusually accessible. Embryos can be marked, cut, pasted and cultured in simple saline solutions, giving access to the earliest inductive interactions as well as gene regulation and function assays. As with all manipulative procedures, prac- tice is the key, but good tools are essential. These are dis- cussed, from the most suitable forceps to the curvature of a good eye-brow knife. ‘The development of wholemount staining and in situ hybridization procedures has circum- vented the obfuscations of the yolk and produced exciting new views of embryos.

Another way of dealing with the yolk is to eliminate it by centrifugation. The viscous supernatant obtained still per- forms a considerable number of cellular activities from chro- matin and nuclear assembly to mitosis and DNA repair. These are amongst the model systems discussed in part 4. The variety of activities sustained in these extracts again relies in the special features of the material - the stock piles of components built up in oocytes, the size of the cells, and the availability of large quantities of material at defined stages.

This is a wide ranging book with its primary emphasis on methodologies. The approaches, however, are discussed so that often it is apparent not only how something is done, but why. It is an invaluable source book for any lab worlung, or intending to work with Xenopus.

’ Chris Ford, School of Biological Sciences, University of ! Sussex, Fulmer, Brighton BN1 9QG, UK.