A new study from the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa suggests that stem cells intentionally break their own DNA as a way of regulating tissue development. The study, published in Proceedings of the National Academy of Science (PNAS), could dramatically change how researchers think about tissue development, stem cells and cancer.
Human cells contain 46 strands of DNA that code for all our genes. Certain chemicals and UV light can break these strands into pieces, a process that has traditionally been considered a bad thing, leading to cell death or diseases such as cancer if the damage is not repaired quickly. The new research, led by Dr. Lynn Megeney, shows for the first time that stem cells will intentionally cut and then repair their own DNA as a mechanism of activating genes that promote the development of new tissues.
The project started as an attempt to understand how stem cells give rise to new muscle fibres. In 2002, Dr. Megeney and his team discovered that this process of producing new muscle was somehow connected to another important process called programmed cell death, which the body uses to get rid of unwanted cells. When they blocked or removed a key death-promoting protein called caspase 3, they found that stem cells stopped producing new muscle fibres.
"This discovery was very controversial at the time, but dozens of research groups have now reported that cell death proteins control the maturation process of most stem cell types," says Dr. Megeney. "In the last few years, the big mystery has been how cell death proteins manage this complex process."
Now in the 2010 study Dr. Megeney and his team believe they have solved the mystery. They have discovered that the novel effect of caspase 3 in stem cells is related to its ability to activate another protein that cuts up the cell's DNA (called caspase-activated DNase) and has also traditionally been associated with pr
|Contact: Jennifer Paterson|
Ottawa Hospital Research Institute