Histones histone code

A model called histone code theory includes more aspects of chromatin regulation which have been identified. The histone code theory predicts that histone acetylation and other posttranslational histone modifications serve as binding sites for regulatory proteins which mediate processes like gene transcription upon recruitment (see Fig. 2b) [3]. In this context histone modifications can be understood as... 

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. 

Jenuwein T, Allis CD Translating the histone code. Science 2001 293 1074. 

Turner BM (2002) Cellular memory and the histone code. Cell 111 285-291... 

Margueron R, Trojer P, Reinberg D (2005) The key to development interpreting the histone code Curr Opin Genet Dev 15 163-176... 

Santos-rosa H, Caldas C (2005) Chromatin modifier enzymes, the histone code and cancer. Eur J Cancer 41 2381-2402... 

The dynamic and differential methylation of lysine residues in histone tails plays a central role in the creation of the histone code and the regulation of chromatin structure and function that the code implies [12]. For example, different lysine methylation marks (KMe) are... 

Corona DF, Tamkun JW (2004) Multiple roles for ISWI in transcription, chromosome organization and DNA replication. Biochim Biophys Acta 1677 113-119 Cosgrove MS, Wolberger C (2005) How does the histone code work Biochem Cell Biol 83 468-476... 

Jenkins T (2000) Targeting multi-stranded DNA structures. Curr Med Chem 7 99-115 Jenuwein T, AlUs CD (2001) Translating the histone code. Science 293(5532) 1074-1080 Juan LJ, Utley RT, Adams CC, Vettese-Dadey M, Workman JL (1994) Differential repression of transcription factor binding by histone HI is regulated by the core histone amino termini. EMBO J 15 6031-6040... 

Legube G, Linares LK, Tyteca S, Caron C, Scheffner M, Chevillard-Briet M, Trouche D (2004) Role of the histone acetyl transferase Tip60 in the p53 pathway. J Biol Chem 279 44825 4833 Linggi BE, Brandt SJ, Sun ZW, Hiebert SW (2005) Translating the histone code into leukemia. J Cell Biochem 96 938-950... 

Ito T (2003) Nucleosome assembly and remodehng. Curr Top Microbiol Immunol 274 1-22 Ito T, Tyler JK, Kadonaga JT (1997) Chromatin assembly factors a dual function in nucleosome formation and mobilization Genes Cells 2(10) 593-600 Ivanovska I, Khandan T, Ito T, Orr-Weaver TL (2005) A histone code in meiosis the histone kinase, NHK-1, is required for proper chromosomal architecture in Drosophila oocytes. Genes Dev 19(21) 2571-2582... 

In contrast to simple charge neutralization effects, the effects on protein recog-nition/recruitment are collectively referred to as the histone code . This hypothesis predicts that specific patterns of histone tail acetylations and other modifications serve as epigenetic marks for distinct sets of regulatory proteins to differentially modulate chromatin structure and function (Strahl and Allis, 2000 Turner, 2000 Jenuwein and Allis, 2001). Indeed, several recent findings have demonstrated that histone acetylation creates a signal for the binding of a bromodomain which has... 

Agalioti T, Chen G, Thanos D (2002) Deciphering the transcriptional histone acetylation code for a human gene. Cell 111 381-392... 

Yet another example of combinatorial histone codes come to fore in yeast, wherein H2B K123 monoubiquitination was shown to be a necessary prerequisite for H3K24 and H3K79 methylation resulting in opening of the chromatin (Sun and Allis, 2002). Combination of histone marks in the regulation of physiologically relevant processes such as embryonic development and lymphocyte maturation have also been described. 

Eomeris E, Binda C, Vanoni MA, BattagUoli E, Mattevi A (2005) Human histone demethylase LSDl reads the histone code. J Biol Chem 280 41360-41365 Erye RA (2000) Phylogenetic classification of prokaryotic and eukaryotic Sir2-like proteins. Biochem Biophys Res Commun 273 793—798... 

Figure 6 Cartoon of histone posttranslational modifications. Histone proteins are known for having multiple numbers of the same posttranslational modification and multiple types of posttranslational modifications on their lysine tails responsible for binding DMA. The histone code as it is called relies on the dynamic nature of phosphorylation, acetylation, and mono-, di-, and trimethylation.

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