Structural Choromsomal Hierarchies and Gene Expression

[BillTre]

There have been occasionally questions/comments about gene control. This should feed the hunger for knowledge.
Here is an open access review article: Three-Dimensional Genome Organization and Function in Drosophila.

It discusses some not widely known aspects of control of gene expression in Drosophila and at least some other metazoans (multi-cellular animals), including mammals.
The main idea is the 3D structure of the DNA /chromosomes is involved in control gene expression, and proteins binding specific sequences are important to that.
Loops of DNA are involved in how this works, and there are some diagrams illustrating the ideas.

The complex functioning of the nucleus's information machine is amazing!
The work to figure it out is impressive!

 

[Ygggdrasil]

The three-dimensional organization of DNA in the nucleus and its dynamics (sometimes referred to as the 4D nucleome) is definitely a very hot topic in biology right now and many are working to try to develop new tools to study the question. It's still somewhat nebulous the extent to which all of this organization is important in controlling gene expression and how these mechanisms are regulated. Various labs have published some interesting papers proposing physical models (based on the action of "loop extrusion" enzymes) to explain some of the data on how these "topologically associating domains" form:
http://www.pnas.org/content/112/47/E6456.long
http://www.sciencedirect.com/science/article/pii/S2211124716305307

 

[BillTre]

Here's a nice you tube movie illustrating how the loop extrusion mechanism is supposed to work.
It makes it clear how things don't get tangled up.

Guess you might call it anti-entanglement!