Supreme survivors

Bacteria are fascinating organisms. Despite living in the world's least pleasant habitats, they do not simply survive, they flourish. One trivial reason for taking them seriously is that there are far more of them than there are of us. A more serious reason is that they underpin life as we know it (and, incidentally, a small number of pathogenic bacterial species underpin death).

Most bacteria contain a few thousand genes and, somehow, they contrive to marshal these genes to ensure their survival. To do this, they arrange to make different quantities of each gene product, and the amount of each gene product that is made is fixed to fit the particular environment in which the bacterium is growing.

The key message of this book is that we are beginning to understand the molecular details of how this regulation occurs. It turns out that the most important regulation is at the step at which the DNA sequence that makes up any particular gene is copied into a "messenger" molecule, RNA. This amazing process, called transcription, has been intensively studied since 1960, when the key biosynthetic enzyme, RNA polymerase, was discovered.

Rolf Wagner tells us all about how RNA polymerase gets distributed between the different genes in a bacterium. The book summarises the bottom line from literally thousands of primary research publications, and results in a map that extends from the fundamentals of the subject right up to the research frontier.

The good news is that there is no better treatment of this topic in 365 pages. The bad news is that the map is rather complex and, as the frontier is approached, the book gets bogged down with detail and jargon. This means that, while the book is a useful source to dip in and out of, as a whole it will be easily comprehended only by the few who are already engaged in researching this subject.

Not so long ago, bacteria provided us with the only easily accessible systems for understanding transcription and its regulation. This is because they grow fast, and they can be easily manipulated, so they are accessible to both genetics and biochemistry. Thus, 20 years ago, we were almost completely dependent on bacteria for understanding the details of RNA polymerase and its preferences. However, as other systems have been developed, this is no longer the case. In other words, bacteria no longer have the monopoly on molecular detail when it comes to understanding gene expression. This means that the real interest with bacteria is to comprehend (and possibly exploit) the biology behind the regulation. If I have a criticism of Wagner's very nice book, it is that he misses this key angle: the reader can easily see the trees but somehow misses the forest.

Steve Busby is professor of biochemistry, University of Birmingham.