Oddly Shaped DNA Structures Found In Human Cells

We've seen 'G-quadruplex structures' before, but a new study shows they are much more prevalent in our genomes than we thought.

By Clay Dillow Posted 01.23.2013 at 5:30 pm 7 Comments

Four-Strand DNA 'G-Quadruplex' JEAN-PAUL RODRIGUEZ via Nature

The above is a digital model of DNA, but it’s probably not the DNA you’re familiar with. The double-helix structure of DNA and RNA--two strings of nucleic acids spiraling around each other and held together by complementary base pairs--is both nearly universally recognized and central to its role as the fundamental vehicles for cell function. But it turns out that a square shaped, four-strand DNA structure (like the one above) is likely more common in our genomes than we previously thought, and that could have important implications for biology.

Four-strand DNA--or “G-quadruplex structures” (the G is for the base guanine)--is nothing new to genetic scientists. It can be easily conjured in the lab via guanine-rich strands of synthetic DNA, for instance, and it has long been thought to occasionally form naturally in biological cells. But a new study published online at the journal Nature Chemistry and conducted by University of Cambridge researcher Shankar Balasubramanian suggests that G-quadruplex structures are more common in natural genomes than we thought, and that they may carry out some important genetic business.

This has particular importance in the field of cancer research. Some researchers have previously suggested that these quadruplexes can be found in places along the genome where gene regulation occurs. Errors in gene regulation are, of course, one of the root causes of the kinds of abnormal cells that lead to cancerous cell replication. So the Cambridge researchers engineered an antibody designed specifically to seek out and bind to G-quadruplex structures while steering clear of double-helical structures. When introduced to human cells, the antibody bound itself to several sites along the chromosomal chain--not just in the few where the researchers expected it to--reinforcing the idea that G-quadruplex structures are more prevalent in more places than originally thought.

If researchers can figure out all the places where these structures are forming along the genome, they may be able to zero in on the places where genetic ailments like cancer get their starts and try to mitigate that process.

[Nature]

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7 Comments

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Robot

01/23/13 at 7:41 pm

Amazing! We are really a bunch of crochet potholders!
Who knew, lol! ;)

It does of rather explain why some of us are unraveled and others are tied up in knots...
ha,ha... snort.

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Bagpipes100

01/24/13 at 8:44 am

We keep finding more and more uses for various parts of DNA we thought were junk before.....or at least naturalists thought were junk left overs, because it would only make sense that there would be junk left overs if we are all just a bunch of random mutations. And yet we now know due to the ENCODE project that over 80% of our DNA has some functionality.... its as if the naturalists assumptions about life were wrong.

But honestly, we can't take the evidence where it leads us....that's not how "Science" is done.

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Robot

01/24/13 at 8:53 am

"Breakthrough study overturns theory of 'junk DNA' in genome"

www.guardian.co.uk/science/2012/sep/05/genes-genome-junk-dna-encode
................................
"Hidden Treasures in Junk DNA"

www.scientificamerican.com/article.cfm?id=hidden-treasures-in-junk-dna
................................
"Bits of Mystery DNA, Far From ‘Junk,’ Play Crucial Role"

www.nytimes.com/2012/09/06/science/far-from-junk-dna-dark-matter-proves-crucial-to-health.html?pagewanted=all&_r=0

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HBillyRufus

01/24/13 at 9:43 am

Yes, Bagpipes, by all means we should throw out all study of evolutionary biology because the theory was not exactly perfect when it was first formulated.

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Bagpipes100

01/24/13 at 12:50 pm

@HBillyRufus,

But it would be nice to give it up at some point. Especially because it has worked as well as a earth centered solar system.

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AnonymousAce920

01/24/13 at 4:22 pm

@Bagpipes100 "But it would be nice to give it up at some point. Especially because it has worked as well as a earth centered solar system."

With the amount of evidence there is for evolutionary biology, it makes very little sense to scrap the whole thing as opposed to revising the theory.

Is it really that hard to grasp that our understanding of natural processes can change based on our observations and data we collect?

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yclaid

01/25/13 at 7:38 am

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