Karl Ekwall

Epigenetics - the conductor of the orchestra

"Performing an orchestral piece is impossible if all the musicians play by themselves. They must follow the directions of the conductor," says Professor Karl Ekwall when explaining the meaning of the term epigenetics that is used for his field of research.

In the allegory with the symphony orchestra epigenetics is the conductor and all the musicians are different genes. Without changing the DNA sequence of the genes epigenetic modifications of

different kinds can control which genes are turned on and off, and how the genes are expressed. The musicians are instructed when to start playing and how the written music should be interpreted.

Karl Ekwall is Professor of Medical Genetics and Epigenetics at the Department of Biosciences and Nutrition. Epigenetic means "above or beside the genes" and epigenetics is a research field that started expanding in the 1990s. It has already changed a lot of the perspectives on genetics and made clear that there is heritable information beyond the genes we inherit from our parents. In addition the environment may influence the epigenetic make up of a person. For example genetically identical monozygotic twins often show epigenetic differences.

Epigenetic processes

Karl Ekwall and his research group study epigenetic processes at a molecular level with yeast cells as a model

system. In the cell nucleus the DNA spirals are coiled around proteins called histones. Four different histones form together a round sphere named nucleosome. The structure of the nucleosomes can be changed , making the chromatin (the complex of DNA and proteins) more or less open.

"The nucleosomes work as a sort of traffic polices, controlling accessibility to genes," says Karl Ekwall, who is also the founder and chairman of the Swedish Epigenetics Network supported by the Swedish Research Council. His group studies a range of epigenetic processes such as histone modifications/nucleosome modeling by enzymes and by small RNA molecules. The researchers also study how different histone variants affect gene regulation and the implications of nuclear organization in a broader sense. The development of new bioinformatics tools for systematic study of the entire epigenome is an important project led by Assistant Professor Peter Svensson.

Cancer applications

In cancer epigenetic mechanisms often contribute. Karl Ekwall is convinced that new epigenetic knowledge will result in new cancer drugs. Some of the projects in his group focuses directly on processes that are important in cancer. One example is the studies of epigenetic mechanisms during normal hematopoiesis and in leukaemia, conducted by Assistant Professor Andreas Lennartsson.

Text: Helene Wallskär