A covalent modification of a histone. Its genomic distribution and associated regulatory state do not by themselves specify chromatin accessibility or causation.
Histone methylation adds methyl groups to selected residues of histones. The position and number of methyl groups affect which binding partners recognize the mark. H3K4 methylation, H3K9 methylation and H3K27 trimethylation therefore cannot be treated as one interchangeable signal. Their distributions can be associated with different transcriptional states, and direct causation requires more than correlation between a mark and gene expression. [ref]
Regulation of heterochromatic silencing and histone H3 lysine-9 methylation by RNAi by Thomas A. Volpe and others. 2002, RNA interference and H3K9-linked silencing
H3K27 methylation is addition of one or more methyl groups to the side chain of lysine 27 in histone H3. Mono-, di- and trimethylated states are different chemical states; a measurement of one is not automatically a measurement of the others. H3K27 trimethylation is particularly associated with Polycomb-mediated gene silencing. [ref]
A mechanistic test distinguishes correlation from catalysis. A purified complex can be supplied with histones and a methyl donor to test transfer, while changing a catalytic region tests whether that activity depends on an intact enzyme. In a cell, the distribution of the mark also depends on recruitment, removal and replacement of histones, not only on total enzyme abundance.
A chromatin complex that catalyses H3K27 methylation, with locus-specific recruitment and developmental functions.
Its catalytic activity deposits H3K27 methylation, including the trimethylated state associated with many repressed developmental genes. Recruitment and recognition of modified chromatin can stabilize a regulatory state while retaining the possibility of later reversal. [ref]
Molecular Biology of the Cell, 4th edition by Bruce Alberts and others. Chapter 7, Chromatin Structure and Gene Regulation
A plant histone methyltransferase participating in the reinforcing relationship between H3K9 methylation and methylated DNA.
A plant histone methyltransferase participating in the reinforcing relationship between H3K9 methylation and methylated DNA.
A plant histone methyltransferase participating in the reinforcing relationship between H3K9 methylation and methylated DNA.
H3K4 methylation modifies lysine 4 of histone H3 with one, two or three methyl groups. The states have different genomic distributions; trimethylation is often enriched near active transcription start regions. A mark can recruit binding factors or reflect ongoing regulatory activity, so enrichment does not by itself prove that the modification initiated transcription. State, genomic location and experimental perturbation are all needed for a mechanistic claim. [ref]
H3K27 trimethylation adds three methyl groups to lysine 27 of histone H3, conventionally H3K27me3. It is associated with Polycomb-linked repression of developmental genes in many eukaryotes. Deposition and removal help regulate the persistence of a chromatin state. A broad marked domain describes a molecular state; demonstrating that the mark is required for repression at a particular gene needs a perturbation that separates it from associated factors. [ref]
Molecular Biology of the Cell, 4th edition by Bruce Alberts and others. Chapter 7, Chromatin Structure and Gene Regulation: Polycomb-associated repression
Articles by others on the same topic
There are currently no matching articles.