Heat shock and development (vol. 17 in a monograph series on results and problems in cell differentiation)

This is the first time a book has been devoted to the effects of heat stress on development and to a discussion of the roles of heat-shock proteins in developme,lt. Its chapters collect together a large number ot' experimental observations, many of them buried, up until now, in the developmental biology, molecular and cell biologyjournal~. TILe first chapters emphasise the pronounced effects of stre.~s on developmental events. Heat and chemical stressors are well-known teratogens, their action on certain key proteins of development being the probable reason that stress often exerts dramatic effects on embryonic morphology. A conditioning pretreatment with mild heat shock can often protect against these teratogenic effects, as discussed in detail for the snail, L),mnea stagnalis, for the fruit fl~, Drosophila melanogaster, and for mammalian embryogenesis. In metazoans this protective acquisition of tolerance is usually attributed to the synthesis of stress (heat-shock) proteins. However, there is a general tendency of the text to ascribe total attribution of acquired thermotolerance to these proteins and to ignore the possibility that physiological changes caused by a mild preconditioning stress treatment may also play a role in the acquisition of stress tolerance. A single chapter describes the use of heat-shock promoters for investigating untimely or eetopie expression of developmental proteins, a useful experimental approach that has helped unravel many of tile factors controlling Drosophila development. Later chapters are devoted to the eell-specilic and developmental control of stress protein synthesis. They lead us through heat-shock protein synthesis in plant tissues, seed development and germination, pollen development and germination; in the development of Drosophila and Xenopua; and finally in mammalian gametogenesis and embryogenesis. Stress proteins are often induced quite independently of stress, in response to control of the cell cycle, viral infections or exposure to cytokiues. Also the heat-shock inducibility of these proteins is strangely altered in certain specialized cell types or even completely absent in certain early embryonic states. The detailed consideration given to how stress proteins and stress protein genes participate in these phenomena makes this text fascinating reading and a valuable supplement to the several books and review article~ now published on the heat-shock response. Peter Piper