Genome complexity: 3-D arrangement (Introduction)

by David Turell , Wednesday, March 15, 2017, 14:33 (2811 days ago) @ David Turell

Now visualized in mammalian cells:

https://www.sciencedaily.com/releases/2017/03/170313135018.htm

"Scientists have determined the first 3D structures of intact mammalian genomes from individual cells, showing how the DNA from all the chromosomes intricately folds to fit together inside the cell nuclei

" Using their new approach, the researchers have now been able to determine the structures of active chromosomes inside the cell, and how they interact with each other to form an intact genome. This is important because knowledge of the way DNA folds inside the cell allows scientists to study how specific genes, and the DNA regions that control them, interact with each other. The genome's structure controls when and how strongly genes -- particular regions of the DNA -- are switched 'on' or 'off'. This plays a critical role in the development of organisms and also, when it goes awry, in disease.

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"Professor Ernest Laue, whose group at Cambridge's Department of Biochemistry developed the approach, commented: "Knowing where all the genes and control elements are at a given moment will help us understand the molecular mechanisms that control and maintain their expression.

"'In the future, we'll be able to study how this changes as stem cells differentiate and how decisions are made in individual developing stem cells. Until now, we've only been able to look at groups, or 'populations', of these cells and so have been unable to see individual differences, at least from the outside. Currently, these mechanisms are poorly understood and understanding them may be key to realising the potential of stem cells in medicine."

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"Dr Tom Collins from Wellcome's Genetics and Molecular Sciences team said: "Visualising a genome in 3D at such an unprecedented level of detail is an exciting step forward in research and one that has been many years in the making. This detail will reveal some of the underlying principles that govern the organisation of our genomes -- for example how chromosomes interact or how structure can influence whether genes are switched on or off. If we can apply this method to cells with abnormal genomes, such as cancer cells, we may be able to better understand what exactly goes wrong to cause disease, and how we could develop solutions to correct this.'"

Comment: As before the 3-D relationships control how genes are expressed and affect each other when they are in close proximity. It is another layer of genome complexity.