Heterochromatin protein 1

Hiragami K, Festenstein R (2005) Heterochromatin protein 1 a pervasive controlling influence. Cell Mol Life Sci 62 2711-2726... 

Stewart MD, Li J, Wong J (2005) Relationship between histone H3 lysine 9 methylation, transcription repression, and heterochromatin protein 1 recruitment. Mol Cell Biol 25 2525-2538... 

SRF 150 has similar requirements Direct interaction not tested Heterochromatin Protein 1 (HPl) Stimulation of SRF binding by SSRPl. Activation... 

Heterochromatin protein 1, binds to heterochromatin and interacts with numerous partner proteins to organize the higher-order structure of heterochromatin... 

As discussed, histones are an integral part of nucleo-somes, the basic repeating structural unit of chromatin. The amino termini of histone proteins can be modified post-translationally by processes that include acetylation, methylation, phosphorylation, and ubiquination. Acetylation of the lysines on the amino termini of histones H3 and H4 by histone acetyltransferases decreases histone-DNA interaction and improves the accessibility of DNA to transcriptional activation. On the contrary, histone deacetylation by histone deacetylases promotes the formation of compact nucleo-somes, leading to repression of transcription. Histone deacetylation is in fact a key component to the assembly of heterochromatin, the transcriptionally inactive chromatin. Methylation of the ninth amino acid residue, lysine, on histone H3 generates a binding site for heterochromatin protein (HP 1) and thus is another key event in heterochromatin formation. Phosphorylation of the tenth amino acid, serine, on histone H3 is important for chromosome condensation and mitosis. 

Zhang CL, McKinsey TA, Olson EN (2002) Association of class II histone deacetylases with heterochromatin protein 1 potential role for histone methylation in control of muscle differentiation. Mol Cell Biol 22(20) 7302-7312... 

Ainsztein, A. M., Kandels-Lewis, S. E., Mackay, A. M., Earnshaw, W. C. (1998). INCENP centromere and spindle targeting Identification of essential conserved motifs and involvement of heterochromatin protein HPl. The Journal of Cell Biology, 143, 1763-1774. 

Lysine 9 of histone H3 is the target of many SET-domain-containing enzymes (Fig. 2). Most of the HKMTs that methylate this residue belong to the Su(var)3-9 family. In Drosophila and humans, methylation of this lysine provides a binding site for the chromo domain of heterochromatin protein 1 (HP1 Aagaard et al., 2000 Loyola et al., 2001). Work done in Drosophila has demonstrated that the interaction of HP1 and methylated... 

Bennett, R.N., Wenke, T., Freudenberg, B., Mellon, F.A. Ludwig-Miiller, J. (2005). The tu8 mutation of Arabidopsis thaliana encoding a heterochromatin protein 1 homolog causes defects in the induction of secondary metabolite biosynthesis. Plant Biology, 7, 348-357. 

Fanti L., Giovinazzo G., Berloco M., and Pimpinelli S. 1998. The heterochromatin protein 1 prevents telomere fusions in Drosophila. Mol Cell 2 527-538. 

Huang D.W., Fanti L., Pak D.T., Botchan M.R., Pimpinelli S., and KeUum R. 1998. Distinct cytoplasmic and nuclear fractions of Drosophila heterochromatin protein 1 Their phosphorylation levels and associations with origin recognition complex proteins. /. Cell Biol 142 307-318. 

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