Epigenetics: Interaction Of DNA Methylation And Chromatin

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Epigenetics: interaction of DNA methylation and chromatin Epigenetics is a field where advances are being made daily. Epigenetics is defined as “heritable changes in gene expression that occur without a change in DNA sequence,” as stated by Dr. Alan Wolffe. A way in which we can understand this definition is by taking the analogy of a card game. The cards, the DNA sequence, have been dealt and will not change, however we need to understand how to play the cards, the rules, which is epigenetics. The guidelines can vary and completely change the way the card game is played and who comes out on top. The rules that are studied and understood through this research paper are those of DNA methylation and chromatin. These changes can produce …show more content…
The first would be that this is not something that is conserved when the DNA is replicated and the second is more active, in which a DNA demethylase (has not been discovered) does the job. Just as there are enzymes that take care of methylating the DNA there are those that work to modify the histones. By acetylating histones there are more gene expression possibilities, this too serves to help open the chromatin structure up so that machinery can access it. Histone acetyltransferase (HAT) acetylates histones and uncoils DNA giving an open chromatin structure. Histone deacetylases (HDAC) on the other hand causes tight coils and a closed chromatin structure, repressing gene expression. There is a connection between cells that are too deacytlated and cancer cells because the cells become silenced. HDAC will form transcriptional co-repressor complexes, two of which are the SIN3 and the Mi2-NuRD. The first of these is involved in interactions with chromatin.

This is a representation of the complexes that are formed, you can see the HDAC components in the two complexes. The sin3 complex is recruited to methylated DNA by interacting with the top groups pictured in the first image. The second image is localized to methylated DNA regions when the MBD3 interacts with MBD2. Chromatin remodeling is the readjusting of the nucleosome positioning and conformation. The