Gene regulation epigenetic mechanisms

Stryer, L., Berg, J.M. and Tymoczko, J.L. (2002). Biochemistry (5th ed.). W.H. Freeman, New York Turner, B.M. (2001). Chromatin and Gene Regulation — Molecular Mechanisms in Epigenetics. Blackwell Science, Oxford... 

Turner, B.M. (2001). Chromatin and Gene Regulation — Molecular Mechanisms in Epigenetics. Blackwell Science, Oxford... 

In higher eukaiyotes, most of the chromosomal DNA carries 5-methyl-cytidine residues located in CpG sequence motives. There is a close correlation between transcriptional inactivation and methylation. On the other hand, considerable evidence shows that regions of DNA that are actively engaged in transcription lack 5-methyl-cytidine nucleotides in CpG motivs. Hence DNA methylation is a means how cells regulate gene expression. DNA methylation which is catalyzed by DNA methyltransferases is the best characterized epigenetic mechanism. 

Russo, V., Martienssen, R., and Riggs, A. (1996) Epigenetic mechanisms of gene regulation. Cold Spring Harbor, NY Cold Spring Harbor Laboratory Press. 

Li et al. 2004). Furthermore, these mice did not exhibit monoclonal OR gene expression, suggesting that OR gene choice is regulated by epigenetic mechanisms. 

Importantly, as we detail later in Section 2.3.2, miRNAs can also regulate gene expression through translational activation, which involves epigenetic mechanisms (27,75). 

Beedanagari SR, Taylor RT, Bui P, Wang F, Nickerson DW, Hankinson O (2010) Role of epigenetic mechanisms in differential regulation of the dioxin-indueible human CYPlAl and CYPIBI genes. Mol Pharmaeol 78 608-616... 

Chromatin is made of repetitive nucleoprotein complexes, the nucleosomes (Wolffe 1998). The Ai-terminal tails of core histones protrude from the nucleosomal surface. Covalent modifications of these tails affect the structure of chromatin and are crucial for gene regulation by epigenetic mechanisms. Some modifications also exist in the globular domain and C-terminal regions (Kouzarides and Berger 2007 Zempleni et al. 2009) (Figure 10.3). 

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