.-..~

MISCELLANEA

This meeting report is based on

contributions by J.H. Well, I. Ohad,

K. Eskins, I. K. Hoober and

J. Ioyard.

He also showed that the D1 ° con- former with a slightly slower elec- trophoretic mobility was a phos- phorylated form of the protein and suggested that it was an obligate intermediate in the degradation path- way. Models for a PSII damage and repair cycle, involving migration of damaged PSII from the grana to the stromal lamellae, repair in the stro- real lamellae and migration back to the grana membranes, were pre- sented by Itzak Ohad (Jerusalem, Israel) and Anastasios Melis (Berkeley, California).

/

/

Chloroplasts are one of a family of interconvertible organelles - the plas- rids - which includes starch-storing amyloplasts and brightly coloured chromoplasts. In plants grown in the dark, etioplasts are present, and they develop into chloroplasts on illumi- nation. Research on signal transduc- tion pathways resulting in chloroplast biogenesis has inevitably concentrated on the involvement of light, perceived either through phytochrome or the blue.light receptor. Molecular ap- proaches for investigating phyto- chrome effects (Elaine Tobin, UCLA)

and blue-light effects (Gerhard Richter, Hannover, Germany) were described, but have not yet provided clear de- tails of the signal transduction path- ways. From studies of plants grown with long-term supplementary far-red illumination, Jan Anderson (Can- berra, Australia) proposed that the photosystems themselves, rather than phytochrome, may be the predomi- nant sensors of light quality. A novel observation of heat shock effects on etiolated plants by Klaus Kloppstech (Hannover, Germany) promises to provide another experimental sys- tem for dissection of signal transduc- tion. Pea seedlings in the dark that received a one-hour heat shock each day showed a circadian rhythm of accumulation of rbcS and cab tran- scripts and developed several mor- phological changes characteristic of plants grown in the light. Chloroplast development clearly responds to a variety of environmental factors, and the challenge for the future is to understand the complex web of sig- nals affecting the expression of nuclear and chloroplast genes in- volved in chloroplast biogenesis.

References 1 SHIMADA, H. and SUGIURA, M.

(1986) Nucleic Acids Res. 19, 983-995 2 HOCH, B. et al. (1991) Nature 353,

178-180 3 MULLET, J. E. (1988) Annu. Rev. Plant

Physiol. Plant Mol. Biol. 39, 475-502

Cancer b io logy - a w i d e r v i e w

An Introduction to the Cellular and Molecular

Biology of Cancer (2nd edn)

edited by L. M. Franks and N. M. Teich, Oxford University Press,

1991. £22.50 (xiv + 558 pages) ISBN 0 19 854734 X

Yet another publication on the molecular biology of cancer? Yes, but with a difference. In their preface to the first edition of this book (1985) the editors pinpointed a need for presenting an overview of all aspects of cancer research that was suitable for research workers just entering

the field. They were right, and the book was a great success. Almost all the book's contributors have at one time been associated with the Imperial Cancer Research Fund (ICRF), and this, like many other Cancer Institutes worldwide, has a di- verse portfolio of research interests. However, most newcomers to these institutions enter with specialized interests, such as molecular biology, chemistry, immunology and on- cology, and I agree with the editors that everyone benefits from being aware of what is happening in other areas. The first edition of this book set out to address this problem, with 18 chapters summarizing all current aspects of cancer research. Unlike the editors in the preface to this second edition, I am not surprised that the book already required updating. Unravelling the genetic basis of human cancer has been and still is at the cutting edge of cancer research and no book can be complete with-

out a proper discussion of these advances. A lot has happened in the last five years, including the cloning of the first tumour suppressor gene, and a book with an out.of-date sec- tion on oncogenes and tumour sup- pressor genes would not survive very long. This second edition was there- fore essential.

I very much enjoyed reading this book and I can't think of anyone who wouldn't learn something! For the molecular biologist sequencing endless stretches of DNA or the bio- chemist immunoprecipitating yet another phosphotyrosine-containing complex, it is easy to forget what cancer is all about. This book pre- sents the wider picture, and any new student or postdoc should read it cover to cover. They ought to know that the multistep process of cancer was revealed by epidemiology (chapter 3), that the most important phenotype o.f a cancer cell as far as the patient is concerned is not its

58 TRENDS IN CELL BIOLOGY VOL. 2 FEBRUARY 1992

MISCELLANEA |MmU~'IBnlllnlilAl

ability to grow in soft agar but its metastatic potential (chapter 2) and that therapeutic intervention is saving more and more lives (chapters 1S-18) but further progress would now clearly benefit from some new cellular targets and some novel delivery systems.

I think that the young clinician entering a research lab to do 'cancer research' has a difficult problem. The discovery of oncogenes and tumour suppressor genes has been one of the outstanding achievements of the 1980s, and has inspired many clini- cal oncologists to do basic research. However, most workers in the field have already accepted that this is just the beginning; genes encode

proteins - they might not be as sexy as their progenitors but it is the complexity of protein-protein inter- actions that defines normal cell behaviour. A complete understanding of the cancer process, even when many of the genetic players have been defined, can only be achieved through some serious biochemistry, to elucidate the pathways and feed- back loops that regulate cell growth and behaviour. The days of fishing around to find whether oncogene X is overexpressed in tumour Y are limited. The clinician who has acquired molecular skills will now have to rediscover biochemistry.

I think everyone in cancer research will probably regard three or four

chapters in this book as being their speciality. There are many mono- graphs covering these individual disciplines already and in more detail. The strength of this book lies in the other 15 or 16 chapters. It's an opportunity, under one cover, to get up to date with all the major areas of cancer research - in suf- ficient depth to appreciate the prob- lems and future outlook but without being put off as a nonspecialist (the chapter on epidemiology comes closest to being too detailed). The editors have done a good job in putting this book together; they should not, however, be surprised when a third edition is required in 1996.

Alan Hall

Institute of Cancer Research, Chester Beatty Laboratories, Fulham Road, London SW3 6IB, UK.

If yeasts, why not cillates?

Cellular Aspects of Pattern Formation: The Problem of Assembly (Monographs in

Developmental Biology, Vol. 9)

by G. W. Grimes and K. J. Aufderheide, Karger, 1991. £45.70 (ix + 94 pages) ISBN 3 8055 5382

Problems of morphogenesis and pat- tern formation at the cellular level have long been a major preoccu- pation of 'ciliatologists', a slightly eso- teric sect of biologists. Because ciliates display such a complex organization and are so diverse in morphology and morphogenetic strategies, and also because these bizarre organisms were sometimes considered as an evolutionary dead end, it has been difficult for nonciliatologists to ap- preciate what their study could reveal and how it could be gener- alized. Thus, ciliates have generally been overlooked. The tide is chang- ing. Since Drosophila has revealed homeoboxes and yeasts have con- tributed so greatly to the dissection of the cell cycle, biologists have become receptive to what the study of lower organisms may offer. They now believe that even 'the yeast cell, while lacking some interesting behaviours of higher cells, possesses an experimental advantage in its

simplicity' and may present an 'opportunity to genetically dissect the molecular pathways that lead to the development of cell polarity q. If yeasts are suitable, why not ciliates?

It is therefore time to advertise an important concept in cell biology, that of 'directed assembly', which was experimentally documented some 30 years ago from studies by Sonneborn and colleagues on the ciliate Paramecium. These studies essentially showed that microsurgi- cally induced or 'natural', accidental modifications in the cortical pattern were self-perpetuated through hun- dreds of cell divisions, in the absence of any modification of the genotype. These observations showed that genes do not specify, or suffice to specify, all details of cell architec- ture, and that preformed cell struc- tures play a role in cell heredity by guiding the assembly of newly formed supramolecular structures (in this particular case, ciliary basal bodies and their associated polarized ciliary rootlets).

This is essentially the subject of the little book by Grimes and Aufderheide. The first part presents the concept of 'directed assembly'. This is an old notion, at least in its general initial formulation 'omnis cellula e cellula' (every cell comes from a cell). It is here rejuvenated and more precisely applied - to the mechanisms of assembly of supra- molecular structures like bacterial flagella, ciliary basal bodies, and cortical patterning in Paramecium (as beautifully illustrated on the front cover). In the second part, the exten- sion of the concept to mechanisms operating in metazoa is discussed, with emphasis on microtubule-

TRENDS IN CELL BIOLOGY VOL. 2 FEBRUARY 1992

organizing centres, their role in the organization of the cytoskeleton and the cortex of the egg, and the gen- eral influence of the localization of organized cellular components in the maintenance of cell architecture and in the control of development. Finally, the third part (to me, the most original one) is devoted to evo- lutionary aspects of directed as- sembly - to the likelihood that some accidental changes in shape, size or pattern might be perpetuated pro- vided that they remain within a stability range compatible with the genotype or, in other words, that a given genotype can accommodate more than one organizational pheno- type. Conversely, similar patterns or supramolecular structures may in- volve different molecular compo- nents in different species. Therefore, the evolution of cellular organization and of gene structure may not be strictly coupled.

In the era of molecular biology and molecular phylogenies, it is worth reminding biologists that a descrip- tion of the structure of genes and their products does not alone account for the phenotypes of cells and organisms. The basic supporting evidence for this view, derived from studies on ciliates, is presented here in a remarkably simplified form, both in the text and in the figures and schemes. My only difficulty in evaluating the book was imagining the readership for which it was intended, but it should be accessible to all who are interested in general biological problems.

Reference 1 DRUBIN, D. G. (1991) Ce//65,

1093-1096

lanine Beisson

Centre de G~n~tique Mol~culaire, CNRS, 91198 Gif-sur-Yvette Cedex, France.

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