Histone methylation

Histone methylation

Histone methylation is the modification of certain amino acids in a histone protein by the addition of one, two, or three methyl groups.

Function

This modification alters the properties of the nucleosome and affects its interactions with other proteins.

* Histone methylation is generally associated with transcriptional repression.
* However, methylation of some lysine and arginine residues of histones results in transcriptional activation. Examples include methylation of lysine 4 of histone 3 (H3K4), and arginine (R) residues on H3 and H4.

Demethylation

For many years histone methylation was thought to be a permanent modification. Very recently two families of histone demethylating enzymes were discovered.
* The first was Lysine Specific Demethylase 1 (LSD1) which is an flavin-dependent monoamine oxidase which can demethylate mono- and di-methylated lysines, specifically histone 3, lysines 4 and 9 (H3K4 and H3K9). This enzyme cannot demethylate tri-methylated lysines and for a short while it was thought that tri-methylated lysines may indeed be permanent modifications.
* In late 2005 the Jumonji domain-containing (JmjC) histone demethylases were discovered which are able to demethylate mono-, di-, or tri-methylated lysines thereby disproving the theory that histone methylation is permanent once and for all.

ee also

*methylation

ODD


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Histone — Structure d un nucléosome. On distingue les extrémités N terminales des histones se projetant à l extérieur de la partie globulaire du nucléosome Les histones sont des protéines très riches en acides aminés basiques, que l on trouve dans le noyau …   Wikipédia en Français

  • Histone-Modifying Enzymes — The packaging of the eukaryotic genome into highly condensed chromatin makes it inaccessible to the factors required for gene transcription, DNA replication, recombination and repair. Eukaryotes have developed intricate mechanisms to overcome… …   Wikipedia

  • Methylation — In the chemical sciences, methylation denotes the addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group. Methylation is a form of alkylation with, to be specific, a methyl group, rather than a larger… …   Wikipedia

  • Histone methyltransferase — protein Name = euchromatic histone lysine N methyltransferase 1 caption = width = HGNCid = 24650 Symbol = EHMT1 AltSymbols = EntrezGene = 79813 OMIM = 607001 RefSeq = NM 024757 UniProt = Q9H9B1 PDB = ECnumber = 2.1.1.43 Chromosome = 9 Arm = Band …   Wikipedia

  • Histone H1 — Histone Structure d un nucléosome. On distingue les extrémités N terminales des histones se projetant à l extérieur de la partie globulaire du nucléosome Les histones sont des protéines basiques en contact étroit avec l ADN. À ce jour, cinq… …   Wikipédia en Français

  • Histone deacetylase 2 — Histone deacetylase 2, also known as HDAC2, is a human gene. PBB Summary section title = summary text = This gene product belongs to the histone deacetylase family. Histone deacetylases act via the formation of large multiprotein complexes and… …   Wikipedia

  • Histone deacetylase inhibitor — Histone deacetylase inhibitors (HDAC inhibitors, HDI) are a class of compounds that interfere with the function of histone deacetylase.Cellular Biochemistry / PharmacologyTo carry out gene expression, a cell must control the coiling and uncoiling …   Wikipedia

  • Histone code — The Histone Code is hypothesized to be a code consisting of covalent histone tail modifications. Together with other modifications such as DNA methylation it is part of the epigenetic code.The main role of histones is in associating with DNA to… …   Wikipedia

  • Histone acetylation and deacetylation — In histone acetylation and deacetylation, the histones are acetylated and deacetylated on lysine residues in the N terminal tail and on the surface of the nucleosome core as part of gene regulation. Typically, these reactions are catalyzed by… …   Wikipedia

  • Histone — In biology, histones are the chief protein components of chromatin. They act as spools around which DNA winds, and they play a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long. For example, each human… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”