Talk:Histone methylation

Histone methyltransferases are enzymes which transfer methyl groups from S-Adenosyl methionine onto the lysine or arginine residues of the H3 and H4 histones. The histone methyl transferases are specific to either lysine or arginine. The lysine specific transferases are further broken down into whether or not they have a SET domain or a non-SET domain. These domains specify exactly how the enzyme catalyzes the transfer of the methyl from SAM to the transfer protein and further to the histone residue. The methyltransferases can add 1-3 methyls on the target residues. These methyls that are added to the histones act to regulate transcription, the integrity of the genome and epigenetic inheritance.^[1] Inheritable changes in the expression of genes that are not based on changes at the DNA level are the basis of epigenetics. Modifications made on the histone have an affect the genes that are expressed in a cell and this is the case when methyls are added to the histone residues by the histone meythltransferases. Histone methylation plays an important role on the assembly of the heterochromatin mechanism and the maintenance of gene boundaries between genes that are transcribed and those that aren’t. These changes are passed down to progeny and can be affected by the environment that the cells are subject to. ^[2]

After fertilization one of the two X chromosomes in a female organism is inactivated for the purpose of not over producing many of the sex-linked traits that are on these chromosomes. To do this one of the x chromosomes has a high rate of methylation, which causes the unused chromosome to tightly pack itself into the histone to form what is called heterochromatin. This X inactivation occurs throughout many divisions of the cell and recently it has been shown that H3−Lys9 methylation is retained throughout mitosis, giving insight that this could possibly be the epigenetic source of the inactive X.^[3]

Mutations to either methyltransferase, demethyltransferase, or to the histone themselves can have dire consequences for an organism and for the genes that must be transcribed to keep the organism functioning. Certain types of mutations in proteins such as isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2) can cause the inactivation of histone demethyltransferase which in turn can lead to a variety of cancers, gliomas and leukemias, depending on in which cells the mutation occurs. ^[4] — Preceding unsigned comment added by Trepiccc (talk • contribs) 21:08, 22 March 2013 (UTC)

Aadharm (talk) 16:40, 14 March 2013 (UTC)

Trepiccc (talk) 16:41, 14 March 2013 (UTC)

Mcrippen (talk) 16:43, 14 March 2013 (UTC)

There is a clear contradiction in the article:

1. Methylation turns the genes "on".
2. Methylation is associated with transcriptional repression.

--AngelHerraez (talk) 16:08, 11 February 2011 (UTC)

The wikipedia page for the topic Histone Methylation is only a stub. It contains only the basic information on what the main purpose of Histone methylation is to the expression of genes as well as the where the methylation occurs on the histone, but little else. We, (Aadhar, Meghan and Colin), would like to expand this article by including more on how the methylation occurs, why it occurs, and the consequences of methylation on the current organism as well as future generations.

Topics:

Mechanism: Lysine and arginine residue structure and charge Degrees of methylation (mono-, di-, or trimethylation) and related function Positions that can be methylated Structure of histone and tails related to DNA structure Connection to transcriptional control Reversibility Methyltransferase: Structure S-adenosyl-methionine as the methyl group donor related diseases (cancer, Epigenetics: Discuss how certain genes are either activated or inactivated at birth how these are often passed down from one generation to another Histone methylation role in the activation or in activation of such genes Inactive X: Brief discussion of what inactive X is how histone methylation plays a large role Consequences of mutations: IDH mutation induces histone methylation increase in CNS-derived cells and can alter cell lineage gene expression. affects gene expression and development

Researchers look at methylation patterns to determine if cells are cancerous. — Preceding unsigned comment added by Trepiccc (talk • contribs) 22:59, 6 February 2013 (UTC)

I have made several edits of different typos and grammar mistakes that are noted specifically in the edit history of the page. This article is very thorough and has tons of information and is organized in a very logical and comprehensive way. I am not sure what it looked like before your editing, but I am sure much needed information has been added. Generally speaking, the writing could be trimmed in some sections to be more concise. For instance the first four sentences of the "Histone Methyltransferase" section do not flow very well, and could be synthesized into one or two sentences. I have the following suggestions which I have organized by section. Furthermore, there is a need to give far more links to other Wikipedia pages.

Introduction: This section, I believe, should be a bit longer and give a more comprehensive summary of the information which is on the page. While the subsections are very dense, the introduction is your chance to give a synopsis/overview for the person who may not want all of the detail that is laid out in the following paragraphs.

Function: Why does the "activation" hyperlink to the operon page? If you are going to keep that maybe you should explain where operons come into play.

Mechanisms: You may want to mention other types of histone modifications to give a broader scope of what is happening. Also, you say "Studies of these sites have found that that methylation of histone tails at different residues serve as markers for the recruitment of various proteins or protein complexes that serve to regulate chromatin activation or inactivation." What proteins are recruited and this statement probably needs a reference as well.

Histone Methyltransferase: This section has a lot of details, particularly when there is a whole page on histone methyltransferase. Perhaps this section should give a more general view of the function of histone methyltransferase and maybe a brief bit about its structure and why it is so good at interacting with histone tails.

Mutations: I started a new paragraph when the topic of cancer arises as before the transition was awkward and interupted the flow of the article.

References: Still need to include page numbers on the Gilber reference. Also, the section could be improved by adding DOI numbers to the journal articles that don't have them.

Hope these suggestions help. Mannintg (talk) 01:03, 10 April 2013 (UTC)

Hello group, I felt that you guys have done a great job in editing this wikipedia page and turning it from a stub to a pretty informative wikipedia page. I felt that you guys have hit the major topics regarding histone methylation and have explicated the information in these topics very nicely. However like all other wikipedia pages, there is some need for improvement.

I think that the major issue with your page thus far is the fact that you should concise/divide you information a little more. There are some lengthy paragraphs in your page, and it would help readers follow the information about the subject if it flowed a little better. Especially readers who don't have much background on histone methylation.

I also believe that you need more references to current work on the subject as well as where you are drawing your information from. I saw this particularly in the paragraph on mechanisms in which you mention the studies that are being conducted that serve to explore the activation of proteins. Maybe go into a little more detail about what they are looking into with their research. I think that it is always important to discuss why this work is relevant so maybe if you discuss the goals of research in this field it would give new relevance to the subject.

I also think it would be helpful to have a paragraph specifically on disorders. I see that you guys started mentioning how mutations in histone methylation cause cancer, which I believe is a very good topic to hit, but should have its own paragraph. I also think it should go into more detail on other disorders that occurs via mutations in this process.

Lastly, going off research, I believe you guys should have a paragraph on techniques. It is always helpful to explain to people how research is done to explore this process, as well as other academics.

Overall I believe you guys did a great job and should keep up the good work. DrLinguini (talk) 02:21, 14 April 2013 (UTC)

Hey guys, Great job! I thought that the page was very informative and easy to digest. I think that there are many opportunities to link other pages through trigger words such as "epigenetics," "histone methyltransferase," etc. I did link words myself, as I was reading through as well.

Another possible suggestion could be to add more information on how this relates to genetic imprinting. I added a sentence or two at the end of your "Histone methylation in X chromosome inactivation" section that briefly touches on genetic imprinting. This could definitely be expanded to touch upon link-able topics, such as X-inactive center (Xic) and Barr Bodies as well. Lastly, I added genetic imprinting to your "see also" reference list.

All in all, I am definitely impressed with the page, and all your hard work definitely shows! Great job! jeenah92 (talk) 05:15, 14 April 2013 (UTC)

Hi team! Smallman12q (talk) nominated 9 articles from our class for "Did you know" section and your site is going to be up there tonight! Very exciting. This will help bring editors to your site AND you might even get someone that does the page ratings to check out your post and elevate from a C rating (a tag placed on your site before you did all of this work.). Since the Did You Know will certainly bring people to your page, focus on polishing it even more, soon!

An FYI, anyone can change the page ratings according to the quality scale. I can bump it up to a B once you add in some wikilinks (one wikilink/section is not enough) and use consistent referencing (you should use citation templates). Histone should be wikilinked at least once. You should also have a brief history section. A B article typically is "is mostly complete and without major problems, but requires some further work to reach GA."Smallman12q (talk) 00:28, 11 April 2013 (UTC)

Thank you so much for the nomination!! We will definitely look into the addition of a history section and continue working on the referencing! Mcrippen (talk) 03:14, 11 April 2013 (UTC)