New York, NY, April 11, 2012 Chromosomes are strands of DNA that contain the blueprint of all living organisms. Humans have 23 pairs of chromosomes that instruct how genes are regulated during development of the human body. While scientists have developed an understanding of the one-dimensional structure of DNA, until today, little was known about how different parts of DNA are folded next to each other inside the nucleus.
Using a powerful DNA sequencing methodology, researchers at the Ludwig Institute for Cancer Research have now investigated the three-dimensional structure of DNA folds in the nucleus of a chromosome. The findings published in the April 11 issue of Nature provide scientists with a greater understanding about the basic principles of DNA folding and its role in gene regulation.
"In any biology textbook, when you look at a diagram of how genes are depicted, it is invariably a one-dimensional line. In reality, genes are arranged in such a way that two parts of the gene may be distal to each other linearly, but very close in 3-D," said Dr. Bing Ren, Member of the Ludwig Institute for Cancer Research and Professor of Cellular and Molecular Medicine at the University of California, San Diego. "With the knowledge of how DNA folds inside the nucleus, we now have a more complete picture of the regulatory process of genes. That is the primary reason we sought to tackle this problem." The spatial organization is intimately linked to its role in the body.
Ludwig researchers used a sequencing-based method called Hi-C to examine the 3-D structure of chromosomes. "With this technology, we were able to build a map of pair-wise interactions from each chromosome, and from that, extrapolate the basic folding pattern of the DNA. What we learned is that they fold into many local domains termed topological domains, which are on average one million base pairs in size. By way of comparison, the whole human genome is just over three
|Contact: Rachel Steinhardt|
Ludwig Institute for Cancer Research