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A new genetic model for obesity?

September 25, 2003

A gene involved in fat (lipid) metabolism, and consequently relevant for studies in obesity and diabetes, has been described in Drosophila melanogaster (fruit fly) by a team of researchers in the September issue of Mechanisms of Development.

Luis Teixeira and Nathalie F. Vanzo from the European Molecular Biology Laboratory in Heidelberg, Germany, and their collaborators, describe how this gene, named Lsd2, is involved in fat storage.

Two genes with similar function in lipid metabolism have been previously identified in mammals including man. Teixeira and Vanzo's work, describing a gene from the same family in Drosophila, suggest that these genes must be crucial for life or they would not have been conserved in such diverse organisms as humans and fruit flies.

Drosophila melanogaster is one of the most useful organisms in biological research, particularly in genetics. They are easy and cheap to maintain and have a short life which means many generations can be studied in a short period of time. Moreover, the fruit fly has four extremely large chromosomes each with a unique pattern of light and dark bandswhich facilitates, when genetic manipulated, their identification and the tracing of genetic alterations.

So the fact that this gene was described in Drosophila is an important result because it means a unique opportunity for its study.

Teixeira and Vanzo's work shows that Lsd2 in Drosophila is equivalent to a family of genes previously described in mammals. One of those mammals' genes is called perilipin. It has been shown that, in mice, the lack of perilipin gives rise to individuals with a leaner and more muscular body and also, very interestingly, resistant to diet-inducing obesity. In humans, studies of obese women also showed alterations in perilipin.
As obesity is such a big health problem, the study and possible manipulation of this gene presents numerous possibilities.

Moreover, although for many years lipids were merely associated with cells involved in fat storage or transport, their discovery in many other type of cells has made apparent that their role is probably also much more diverse than previously thought.

In fact while we all know the importance of understanding lipid metabolism in obesity it is now known that alterations in this metabolism are associated with some of the most widespread human diseases, such as arteriosclerosis and diabetes (more than 80% of type 2 diabetics - the most common type of diabetes affecting more than 151 million of people - are also obese). Lipids malfunctions are also associated with viral diseases such as AIDS and some lipids have been involved in the infection mechanism of other viral diseases such as hepatitis C. In conclusion, lipids seem to be linked to a range of life processes from inflammation in mammals to the release of animal pheromones.

Teixeira and Vanzo's work is important not only because it describes a new gene and asserts its importance when shows how it is conserved among distant species but also because it reveals Drosophila as a genetic model for such important gene family.

Observatório da CiÙncia e do Ensino Superior