Archaea microbes fold, twist and contort their DNA in extreme ways

 Erin Foley
AP Bio C Block Odd
Current Event 16
March 15th, 2021

Mega, Emiliano. “Archaea microbes fold, twist and contort their DNA in extreme ways”. 

ScienceNews, ScienceNews.com. https://www.sciencenews.org/article/archaea-microbes-fold-twist-contort-dna-extreme-ways, Mar 11, 2021. 

Recently, archaea were discovered that twist in a manner that has never been seen before. These single-celled archaea microbes pack their DNA into flexible coils that expand and stretch like a slinky, suggesting that they can access their own genetic material very easily. Although Karolin Luger, a Howard Hughes Medical Institute investigator at the University of Colorado Boulder, describes the DNA as resembling a slinky that’s been “forced open like a book”, this unsettling description is offset by the fact that the DNA “actually flows very naturally”. These archaea can spool their DNA around small proteins called histones, just as animals and fungi bend and fold their own genomes into compact, disk-shaped units known as nucleosomes. This information has been known since 2017, but only now do researchers understand what these structures look like in archaea and how the microbes gain access to their spooled DNA. Using computer simulations and electron microscopy experiments on the DNA of archaea, scientists discovered that the DNA of archaea “[open] and [close] in a clamshell motion”. In us humans and all complex organisms, there is sophisticated machinery needed to “unwrap/loosen” our nucleosomes and gain access to specific genes, whereas the archaea simply need to contort their DNA to turn genes on and off. When the DNA is in the “open clamshell” state, genes can be read, otherwise, they cannot be read and are thus turned off. Researchers like Luger now wish to see if these slinky-DNA archaea occur frequently within nature, or if archaea generally use other methods to package and unpack DNA.

An organism’s ability to access DNA is significant in its own right, but the fact that archaea do it in the same way that humans do - by bending and folding - demonstrates that they are more like us than previously thought. For a long time, archaea, single-celled organisms that are found in every environment on Earth - including the human body - have not been understood on the same level that we understand bacteria and eukaryotes. With this new information, we can conclude that archaea are more similar to eukaryotes than they are to bacteria, though one’s instinct may be to believe the opposite. As a result of their similarities, we can use these simple-celled organisms to study human-cell processes such as gene expression, as opposed to studying the extremely complex human cells. Understanding gene expression is key to understanding how genetic disorders and cancers come to be, as well as to understanding all processes as life. Without understanding how proteins are made, we cannot understand life at all, as the differentiability of cells (and the subsequent makeup/function of all organisms) depends on the production of proteins. By studying these simple-celled archaea rather than complex eukaryotes, we are one step closer to understanding these extremely complex processes.

This article was sufficient in illustrating the experiment at hand and describing the results. The author is very descriptive of archaea and how they package their DNA, using visuals to help the reader understand extremely complex topics. For instance, he describes their bending as “molecular gymnastics” and uses an analogy to cassette tapes to explain gene expression/transcription. “Similar to... cassette tapes... DNA stores information in a very thin and fragile filament of nucleic acids... But unlike the tapes, which often tangled and tore, rendering them useless, the genetic material can be read, split into two like a zipper and replicated without tangles and breaks –– all while remaining confined in an incredibly small compartment.” Her figurative language made it easier for me to understand both the topics described in the article as well as concepts we are learning about in class. However, she could have done a better job explaining the significance of the results/archaea DNA packaging. After describing the experiment and the observed results, she ended the article with no explanation of how the DNA packaging methods of archaea are relevant to research. I had to complete additional research in order to write about the significance to society. By highlighting the relevance of these findings, maybe merely saying that gene expression/DNA packaging is a point of interest for researchers, Mega would have made a much more engaging article that left a lasting impression on the reacher.