Histone methylation
Histone methylation is an epigenetic tool for
inactivating as well as activating genes. DNA chromatin is wrapped around
Histone proteins which helps to form chromosomes. Alterations in the histone proteins by epigenetic
factors such as adding methyl groups to the histone structures causes
modifications in the gene expression. There are several types of methylation.
The activating type (H3K4m) adds to the histones in promotor regions of a gene
and activates transcription. Other methylations such as H3K9m and H3K27m on the
other hand cause the gene to be inactivated.
Histone methylation regulates a
variety of biological processes like stress response, DNA repair, cell
differentiation and ageing. It also modifies long-term memory and is an
important factor for learning.
Histone methylation patterns can to a certain extend be inherited, methylation
levels change during the lifespan and have been shown to influence longevity in
several organisms.
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Sources
Greer, E., Shi, Y. Histone
methylation: a dynamic mark in health, disease and inheritance. Nat Rev Genet 13, 343–357 (2012). https://doi.org/10.1038/nrg3173