DNA Methylation controls Blood Cell Decisions

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- In vitro cultivated hematopoietic cells of a mouse. Photo: MDC/S. Ghani
Blood cells live only a limited time. Therefore, the body perpetually creates new blood cells. Their reservoir is constituted by the blood stem cells. Depending on a chemical process long known to researchers, a blood stem cell either turns out to be a stem cell again after cell division or various blood cells develop. Now, a research group led by Dr. Frank Rosenbauer of the MDC has discovered that the level of DNA methylation also controls cell fate decision.
During methylation, methyl groups connect with the DNA. Their distribution on the DNA determines which genes are copied and which are blocked. DNA methylation is of great interest to researchers, since it can be influenced – in contrast to genetic information from environmental factors such as diet. Enzymes (methyltransferases) regulate the process.
“For instance, if the enzyme Dnmt1 is missing, the blood stem cells are defect and the affected mice die”, explains Rosenbauer. When blood stem cells produce some Dnmt1, they survive, but the stem cells lose thei,r potential for self-renewal, and only certain blood cells are created.
Cancer stem cells likewise hardly renew themselves when DNA methylation is very low. In this case, they then also develop less well into leukaemia cells. The MDC researchers now intend to find out why cancer stem cells can be inactivated by a Dnmt1 blockage.









