Genome complexity: 3-D arrangement in bacteria (Introduction)

by David Turell , Thursday, March 23, 2017, 23:40 (2802 days ago) @ David Turell

Now shown in single celled animals:

https://www.sciencedaily.com/releases/2017/03/170323132532.htm

"Researchers have described the 3D structure of the genome in the extremely small bacteria Mycoplasma pneumoniae. They discovered previously unknown arrangements of DNA within this tiny bacteria, which are also found in larger cells. Their findings suggest that this type of organization is a universal feature of living cells.

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"Notably, the CRG team, which counted with the expertise in Mycoplasma from the Serrano's laboratory and the collaboration of the ICREA research professor Marc Marti-Renom at CNAG-CRG, discovered that Mycoplasma's circular chromosome is consistently organised the same way in all the cells, with a region called the Origin (where DNA copying begins) at one end of the structure and the midpoint of the chromosome located at the opposite end. This is a similar arrangement to that seen in some other larger bacterial species.

"Intriguingly, the CRG team found that even the tiny Mycoplasma chromosome is organised into distinct structural domains, each containing genes that are also turned on or off in a co-ordinated way.

"Marie Trussart, the lead author on the paper, said: "Studying bacteria with such a small genome was a big technical challenge, especially because we were using super-resolution microscopy, and it took us five years to complete the project. We had suspected that the Mycoplasma genome might have a similar overall organisation to other bacteria, but we were completely surprised to find that it was also organised into domains, which can be considered as regulatory units of chromatin organisation and that we had identified a previously unknown layer of gene regulation. This research shows that the organisation and control of genes cannot be understood by just looking at the linear sequence of DNA in the genome. Indeed, to get the full picture of gene regulation we need to look at the three-dimensional organisation of the chromatin that also coordinates gene activity."

"The discovery suggests that this level of organisation and genetic control is common to all living cells, from the largest to the smallest, and can be achieved with little more than a handful of DNA binding proteins and the structural properties of the DNA itself."

Comment: Another example of the importance of 3-D DNA relationships. Looks like design.