Epigenetics histones

Thiagalingam S, Cheng KH, Lee HJ, Mineva N, Thiagalingam A, Ponte JF. Histone deacetylases unique players in shaping the epigenetic histone code. Ann N Y Acad Sci 2003 983 84-100. 

Epigenetic histone codes speak with DNA methylation about gene expression... 

An important aspect of the histone code theory is that some modifications can be passed on during cell division. As a result histone modification patterns including histone acetylation serve as a means to store inheritable traits of an organism which are not DNA encoded. This kind of information is generally termed epigenetic information. 

Biel M, Wascholowski V, Giannis A (2005) Epigenetics - an epicenter of gene regulation histones and histone-modifying enzymes. Angew Chem-Int Edit 44 3186-3216... 

Hake SB, Xiao A, Allis CD (2004) Linking the epigenetic language of covalent histone modifications to cancer. Br J Cancer 90 761-769... 

Henikoff S, Furuyama T, Ahmad K (2004) Histone variants, nucleosome assembly and epigenetic inheritance. Trends Genet 20 320-326... 

While some histone variants can become deposited during DNA replication, certain variants also are assembled into chromatin in a replication-independent manner (reviewed in Jin et al. 2005). This allows the incorporation of histone variant into chromosomal regions with high levels of histone turnover. Histone variants can distinguish the affected nucleosomes from their canonical counterparts and are likely to have important function in the specialization of chromatin domains and their epigenetic maintenance. 

In general, the differences in expression and structure of HI variants strongly suggests that variants of linker histones have important roles in chromatin architecture, and might be essential players in the epigenetic control of developmental gene expression. Future studies will be necessary to identify factors that target, modify, and mobilize different linker histones. 

Epigenetic is a term used to describe a state of gene expression that is mitotically and meiotically inherited without any change in the sequence of DNA. Epigenetic mechanisms are mainly of two classes (1) the DNA may be modified by the covalent attachment of a moiety that is then perpetuated. (2) a self-perpetuating protein state may be established (Zelent et al, 2004). The two most studied epigenetic phenomena are DNA methylation and histone tail modifications (Mai et ai, 2005). 

Rice JC, Allis CD (2001) Histone methylation versus histone acetylation new insights into epigenetic regulation. Cutr Opin Cell Biol 13 263-273... 

Dodge JE, Kang YK, Beppu H, Lei H, Li E (2004) Histone H3-K9 methyltransferase ESET is essential for early development. Mol Cell Biol 24 2478—2486 Duan Z, Zarebski A, Montoya-Durango D, Grimes HL, Horwitz M (2005) Gfil coordinates epigenetic repression of p21Cip/WAFl by recruitment of histone lysine methyltransferase G9a and histone deacetylase 1. Mol Cell Biol 280 13928-13935... 

---