Epigenetics Overview

Brief introduction to epigenetic regulation including the the two states of chromatin: euchromatin and heterochromatin.

Transcript

Epigenetic regulation encompasses a number of different modifications to chromatin. These include methylation of the DNA on cytosine bases, a modification that can further be oxidized, as well as modification of the histone tails that emanate from the core of the nucleosome. The tails of core histones labeled here can be altered with distinct chemical modifications including methylation of Histone H3, acetylation of Histone H4, and phosphorylation of Histone H2B. Euchromatin is often characterized by a more open and accessible state of the DNA one in which transcription factors have access to their cognate binding sites and can therefore recruit enzymes like histone acetyl transferases that acetylate histone tails and activate genes by recruiting components of the basal transcriptional machinery, including RNA polymerase. Heterochromatin ,in contrast, is thought to be characterized by a more repressive tight bundling of nucleosomes which impedes transcription factors from gaining access to regulatory sites on the DNA. Methylation of cytosine bases and regions called CpG Islands is a hallmark of transcriptionally repressed heterochromatin. These methylated cytosines in turn recruit proteins like MeCP2 (Methyl CpG binding protein 2) and HP1 (Heterochromatin Protein 1). These proteins are thought to maintain a repressive state of chromatin by inducing histone deacetylation by HDACs as well as histone tail methylation by histone methyltransferase enzymes.

[cellsignaldotcom]

Epigenetic marks such as methylation of DNA and histones were once thought to be quite permanent. However, while we know these marks can be maintained through many cell divisions, recent discovery of DNA and histone de-methylase enzymes have shown these marks to be more dynamic than originally thought. In addition, many studies have shown that environmental variables such as diet and medicines/drugs can alter gene expression and affect long-term epigenetic programming.

[zabelicious]

Great animation!!! Do you have an hypothesis of what might happen when someone is subjected to a traumatic event in terms of repression of gene transcription?

[cellsignaldotcom]

Hi zabelicious, thanks for the question. Due to the character restriction limit, you can find a full response to your question on our website. Check the video description for a link.

[MrClimateCriminal]

I very much want to fully understand this. I am an electrical engineer with no background in biology or biochem. Can you recommend good free or cheap resources for me to educate myself?

[AsmaNawaz]

I need some help....
I want to know names of some diseases which are due to facultative heterochromatin...

[zabelicious]

I appreciate your response to my question however, I wonder how permanent these epigenetic factors might be. You might want to examine what happens when someone takes Ibogaine or Ayahuasca (Two strong alkaline plant medicines). They are believed to detoxify as well as correct most of the symptoms observed in complex PTSD. What do you make of that? As you might already know DMT is involved and I have reason to believe that DMT can re-establish gene expression in a permanent way.

[zabelicious]

Can you see the therapeutic value of this? Why do you think the health authorities in Canada and US are opposed to exploring this kind of approach to mental conditions? They seem to think that having hallucinations is no way to go about it while we have them every time we dream... That is a bit odd, especially knowing that the plant medicine has no harmful side effects when properly guided and that it is not addictive. The proof that we can change the harmful metabolic patterns cannot be denied!

[rooneymara]

Can I please use this animation for a video I am making?