RESEARCHERS at the Stanford University of usa have shown, rather ingeniously, how a puzzling observation in molecular biology might be put to practical use in developing new drugs and finding specific genetic targets of drugs. The observation is one of so-called redundancy: in many organisms, and in respect to many functions, there appears to be more than one gene capable of fulfilling the same function (Nature Genetics, Vol 21, p278-283).
This is puzzling because there is
reason to believe that in most cases, a single copy of a gene is sufficient for the proper functioning of the organism. The exceptional ones define what is known as "haplo-insufficiency", the phenomenon whereby the loss of a single copy of a gene that normally exists in two copies results in a visible change.
What G Giaever and colleagues at the Stanford University have succeeded in doing is to develop a technique for the identification of haplo-insufficient genes in brewer's yeast Saccharomyces cerevisiae. More to the point, they have pinpointed genes that are necessary in two copies when the organism is stressed. The method used by them was based on the premise that a gene which must be in two copies can be expected to display sensitivity to a drug that acts on the product of the gene. Six known drug targets were identified in this manner.
The technique can be easily adapted to other organisms, raising the prospect of a systematic search of all the genetic targets that a particular drug might act on, and that, in turn, would be a powerful input for the design of new drugs.