Epigenetics means literally "above the genes” and refers to modifications in gene expression that do not involve changes in the DNA nucleotide sequence. Epigenetic changes may include chemical modifications to the DNA itself or to DNA associated proteins (e.g., histones) and incorporation of histone variants which alter the chromatin conformation reducing accessibility to gene regulatory sequences. These modifications often result from environmental influences which induce hereditable changes in gene expression. Overall, epigenetic changes either enhance or inhibit gene expression and phenotypic outcome is dictated by the specific combination of epigenetic marks.
Read the blog: Epigenetic mechanisms: new insights on the regulation of autophagy
Epigenetic programs play a crucial role in many biological processes including embryonic development and cellular differentiation. For example, the genome of pluripotent cells is generally highly methylated while the process of differentiation is associated with a loss of DNA-methylation marks. Additionally, pluripotent cells generally have a greater incidence of chromatin in an open state, which is determined by specific histone modifications, while differentiated cells are more enriched in condensed chromatin. Epigenetic mechanisms have been also recently recognized to regulate autophagy, a homeostatic process controlling cellular components.
Abnormal frequency or location of epigenetic marks, often due to the aberrant function of DNA- or histone-modifying enzymes, has been associated with various disease states including cancer and neurodegeneration. For example, hypermethylation of tumor-suppressor genes has been identified as a pro-tumorigenic aberrant epigenetic mechanism.
Explore Antibodies for Chromatin Modifiers
Chromatin Modifiers: Major mechanisms inducing chromatin changes include -
- DNA modifiers: add methyl groups directly to DNA sequences
- Histone modifiers: add or remove acetyl and methyl groups to histones within nucleosomes
- MicroRNAs (~22 nucleotides-long sequences): regulate gene expression at the post-transcriptional level by sequence specific binding to mRNA, which leads to targeted mRNA degradation and inhibits gene expression
- Chromatin remodelers: change the composition and positioning of nucleosomes
Learn more about Epigenetic Machinery