May repair hearts and nerve cells
For instance, stem cells may be able to repair tissue in the heart muscle that is damaged during a myocardial infarction and replace nerve cells that are broken down by Alzheimer´s disease.

When stem cells mature into a certain type of cell and take on a definite function, they begin to age in a controlled and predetermined manner.

“One could say that stem cells are stamped with an “expiration date" during the maturation process. Therefore, all specialised cells in our bodies have a limited lifespan. The reason for this is that the chromosomes´ ends, telomeres, act as a DNA clock that measures the cells´ age. Each time a specialised cell divides, the telomeres´ DNA shrinks. When the telomeres have become too short, the cell can no longer divide and it dies," says Associate Professor Tomas Simonsson, one of the authors of the research article.

Stem cells, as opposed to specialised cells, use a special enzyme to extend the telomeres´ DNA when the cell divides. This continuously resets the DNA clock in stem cells, giving these cells eternal life.

DNA clock
In the most recent issue of Nature Structural and Molecular Biology, a European research team, including researchers from the Sahlgrenska Academy, reports that they have succeeded in revealing, in detail, what happens when the DNA clock is reset.

The researchers have examined the proteins that comprise the central workings of the DNA clock and have studied the molecular changes that control the extension of the telomeres´ DNA and how these changes are linked to the various phases of the cell cycle.

“For the first time, researchers are able to explain the molecular background of the eternal life of stem cells and we now hope that this knowledge will simplify the development of clinically functioning stem cell therapy," says Associate Professor Tomas Simonsson.

Publication: Nature Structural and Molecular Biology
Article: Telomerase recruitment by telomere end-binding protein ß facilitates G-quadruplex DNA unfolding in ciliates
Authors: Katrin Paeschke, Stefan Juranek, Tomas Simonsson, Anne Hempel, Daniela Rhodes och Hans Joachim Lipps
Link to article in Nature Structural and Molecular Biology