Carbohydrates: part of the histone code, epigenetics,DNA transcription

[gravenewworld]

And this is why I'm going to hazard to guess that the next century of biology will be heavily dominated by the study of post translational modifications. The genome only encodes ~26,000 genes, and the entire end product of the genome+epigenetics--the proteome--only is comprised of roughly 100,000 proteins. Far, far too small to define the complexity of life. The entire glycome for reasons such as those listed in the paper is theoretically orders of magnitude more complex than the genome, and none of it can be controlled through manipulation of any codes. Metabolism and metabolic fluxes are the only way to control PTMS. http://www.ncbi.nlm.nih.gov/pubmed/22522719(Interestingly, nutrient exposure, through carbohydrate imprinting into the epigenome, can be passed onto offspring. This may be why children of mothers that have type 2 diabetes are at higher risk for type 2 diabetes themselves.)

 

[Greg Bernhardt]

I'm sorry you are not finding help at the moment. Is there any additional information you can share with us?

 

[gravenewworld]

Not really needing any help, just wanted to stimulate some discussion, as this board has been a little slow. Additional information? Sure, even RNA polymerase II has been shown to be glycosylated with carbohydrates :

http://pubs.acs.org/doi/abs/10.1021/bi0027480
http://www.jbc.org/content/287/28/23549

Additonally, the polycomb and trithorax family of proteins as well as the TET family of proteins are also glycosylated with carbohydrates:

http://www.sciencedirect.com/science/article/pii/S1074552110004503
http://www.cell.com/molecular-cell/abstract/S1097-2765(12)01055-6
http://www.ncbi.nlm.nih.gov/pubmed/23403924In otherwords, nutrients, environment, and space/time are modifying higher order chromatin structure and epigenetics through carbohydrate modifications that heavily regulate genetic transcription, the histone code, and DNA methylation. Carbohydrates are the direct link between metabolism and the epigenome, and changes in genetic transcription that occur in response to environment/nutrients. Furthermore, everyone is now excited about micro RNAs. Well, what transcribes miRNAs? That would be RNA poly II--which, as alluded to above--is glycosylated and heavily regulated by carbohydrates.

It goes even further, virtually all transcription factors are heavily regulated by glycosylation. The majority of known kinases are also glycosylated, and their function absolutely changes based on their states of glycosylation.

I assume these are just a few of the reasons why carbohydrates are called the '3rd alphabet of life' next to DNA and proteins, but what is more interesting (and frustratingly difficult) is the fact that they can not be template controlled like DNA/proteins can. Who ever thought that sugar on your table was such a powerful little molecule eh?