Prokaryotic Gene Expression (Frontiers in Molecular Biology Series, 21).

Simon Baumberg (ed.). Oxford University Press, Oxford. 1999. Pp 325. Price £32.95, paperback. ISBN 0 19 963603 6.

The chapter titles in this monograph whet the appetite for a volume that covers the subject from conception to current analyses of pathogenic bacteria. An instructive, historical perspective from the editor prefaces three foundation chapters concerned with the recognition of specific DNA- and RNA-binding sites by relevant proteins. Appropriately, Peter Stockley starts with a basic introduction to the sequence-dependence of nucleic acid conformations and the recognition potential of Watson–Crick base pairs, before documenting these principles with examples of defined structures. The chapter by John Heldman reviews RNA polymerases and their interactions with promoter sequences and that by Stephen Busby the interactions of repressors and activators with DNA, with each other, and with RNA polymerase. Zhiping Gu and Paul Lovett follow with a survey of modes of post-transcriptional regulation, principally those affecting translation. Karl Drlica and colleagues discuss the subtle effects of DNA topology on gene expression before Regine Hengge-Aronis integrates the control devices into a global regulatory network as currently understood for Escherichia coli. This leads logically to the two-component signal transduction systems reviewed by Mariette Atkinson and Alexander Ninfa. There is no specific review of the role of proteolysis.

Three chapters extend the topic of gene expression in bacteria to important problems of increased complexity. Jon Saunders covers those systems in which genes are switched on and off by one of a variety of novel mechanisms, including the rearrangement of DNA sequences, and Charles Dorman considers control devices relevant to bacterial pathogenicity. Michael Yudkin and Keith Chater combine to provide a lucid account of some of the complex interactions that control the developmental pathways of sporulation and antibiotic production in Bacillus subtilis and streptomycetes. The editor concludes with a brief reflection on evolutionary aspects in which he poses some questions that remain unanswered.

Inevitably, phage systems are mentioned by many authors, nevertheless, I feel that the book rather neglects their significance in the elucidation of basic principles. I was, for example, prompted to return to the enjoyable chapter in Jacob’s autobiography in which, among other things, he documents the significance of his early experiments with phage λ in providing clues to an understanding of the induction of the lac genes. Jacob recognized a parallel between the mutants of λ that conferred a clear-plaque morphology, and repressor-negative mutants of the lac system. He was struck with the realization that zygotic induction of a λ prophage led to the immediate expression of a series of phage genes, suggesting their control as a unit. In his autobiography, The Statue Within, Jacob recalls his appreciation of the λ and lac systems: ‘Where can the repressor act to stop everything all at once? The only simple answer, is on the DNA itself! In one way or another, the repressor must act on the DNA of the prophage to neutralize it, to prevent the activity of all its genes. And by way of symmetry, the repressor of the lactose system must act on the DNA containing the genes of the galactosidase and of the permease’. Jacob persuaded Monod to consider these ideas and the classical model of the operon developed. The anticipation that the mutations in λvir prevent repressor from binding to its target sequences gave confidence in the search for operator-constitutive mutants that would leave the switch for the lac genes set in the ‘on’ position.

I suspect that failure to obtain one transcript on time has delayed publication of the others; the lag between the literature surveyed and publication is commonly 2 years, but occasionally as much as 4 years. The problem of unmet deadlines frustrates the task of publishing a collection of reviews, which together contribute more than a series of independent articles. Perhaps, in the absence of a guaranteed high ‘impact factor’, editors have no ‘carrot’ with which to persuade laggards. Despite this problem the editor has produced a useful monograph.