Edmonton, July 3, 2014 A research team at the Faculty of Medicine & Dentistry at the University of Alberta have discovered a new way by which metabolism is linked to the regulation of DNA, the basis of our genetic code. The findings may have important implications for the understanding of many common diseases, including cancer.
The DNA wraps around specialized proteins called histones in the cell's nucleus. Normally, histones keep the DNA tightly packaged, preventing the expression of genes and the replication of DNA, which are required for cell growth and division. In order for these critical functions to take place, histones need to be modified with the attachment of an acetyl-group, donated by a critical molecule called acetyl-CoA. This attachment relaxes the DNA, allowing for DNA replication and gene expression. This mechanism is called "epigenetic regulation of DNA" and is important for normal functions (like the growth of an embryo or brain functions) or in common diseases like heart failure or cancer. Until now, how the nucleus generates acetyl-CoA for histone acetylation had remained elusive.
The research team, lead by postdoctoral fellow Gopinath Sutendra and professor Evangelos Michelakis in the Department of Medicine, discovered that an enzyme thought to reside only within mitochondria, called Pyruvate Dehydrogenase Complex (PDC), can actually find its way into the nucleus and do what it is designed to do in the mitochondria: generate acetyl-CoA. When in mitochondria, PDC uses the carbohydrates from our diet to generate acetyl-CoA for energy production. When in the nucleus, PDC can produce acetyl-CoA for histone acetylation.
"Although this jumping of an enzyme from one organelle into another in the cell is not unheard off, our results were quite surprising", Sutendra says. "We wanted to measure acetyl-CoA levels and PDC in the mitochondria because that's where we thought they were. But accidentally we had the nuclei isolated
|Contact: Ross Neitz|
University of Alberta Faculty of Medicine & Dentistry