This week’s issue of Science will carry an article out of MIT/Harvard’s Broad Institute that further illuminates the 3-dimensional structure of DNA. The Science article is here, or can be downloaded from Erez Lieberman-Aiden’s (the first author) site. Specifically, the structure described in the article wraps itself in a way such that the (very) long strands of DNA don’t tangle, much unlike that bin you have that’s full of extension cords and other gadgets. This is critical for rapid unravelling of a DNA strand and transcription in to working proteins inside the cell. This newly discovered 3-D structure also apparently puts non-coding areas of DNA in the middle of the structure – kind of like the core of a baseball – it supports the outside structure.
The image above is from the article and shows DNA on the left that’s all tangled – a mess, really. The ball on the right, although it still appears to be quite tangled, has some brilliant structure in that chaos. This structure, according to researchers, helps to hold and regulate DNA on the outside of the ball/structure – you can at least visually see some structure in the form of color fields on the surface of the DNA “ball.” This is only the beginning of our understanding of this fundamental structure of DNA. These structures, I’m betting, will be found all over the genome, playing many, many important roles in how our genes are regulated.
My guess is that the exact make-up of the code inside the 3-D structure/scaffolding actually has an effect on the regulation of the outside coding regions/genes. That is, the inside structure somehow interacts with the outside layers to regulate which sections of coding DNA, aka genes, are up for “decoding” in to proteins. Think of the inside as a scaffolding that supports the ‘important’ gene regions of DNA – but it not only supports, but “holds out” key genes or parts of genes to be de-coded. Different internal scaffold structures could up-regulate genes, while others could down-regulate. My guess is that over time these non-coding and structural regions will prove to actually have functions – structural or otherwise – that play key roles in DNA regulation. While these regions of our DNA code may not be made in to functioning parts of cells, they may play an increasingly more important role in how DNA is de-coded.
Ultimately, I hope that this structure and, in turn, regulation will shed some light on diseases and in better understanding our physiology – which will affect the way we approach the diagnosis and treatment of disease. It’s more illumination that we don’t know what we don’t know – there are many more miles to go.
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