HP1 alpha / Biotin / HP1

Product Details

Description	CBX5 Monoclonal Antibody, Biotin conjugate. Heterochromatin protein-1 (HP1) is a methyl-lysine binding protein localized at heterochromatin sites, where it mediates gene silencing. It has been shown that mammalian methyltransferases that selectively methylate histone H3 on lysine-9 generate a binding site for HP1 proteins, a family of heterochromatic adaptor molecules implicated in both gene silencing and supranucleosomal chromatin structure. High-affinity in vitro recognition of a methylated histone H3 peptide by HP1 requires a functional chromodomain. Thus, the HP1 chromodomain is a specific interaction motif for the methyl epitope on lysine-9 of histone H3. In vivo, heterochromatin association of HP1 proteins is lost in Suv39h double-null primary mouse fibroblasts but is restored after reintroduction of a catalytically active SUV39H1 HMTase. A molecular mechanism through which the SUV39H-HP1 methylation system can contribute to the propagation of heterochromatic subdomains in native chromatin has been defined. It has been demonstrated that HP1 can bind with high affinity to histone H3 methylated at lysine-9 but not at lysine-4. The chromodomain of HP1 as its methyl-lysine-binding domain has been identified. A point mutation in the chromodomain, which destroys the gene silencing activity of HP1 in Drosophila, abolished methyl-lysine-binding activity. Genetic and biochemical analysis in S. pombe showed that the methylase activity of Clr4 (the SUV39H1 homolog) is necessary for the correct localization of Swi6 (the HP1 equivalent) at centromeric heterochromatin and for gene silencing. A stepwise model for the formation of a transcriptionally silent heterochromatin: SUV39H1 places a methyl marker on histone H3, which is then recognized by HP1 through its chromodomain has been suggested. This model may also explain the stable inheritance of the heterochromatic state. SUV39H1 and HP1 are both involved in the repressive functions of the retinoblastoma protein. Rb associates with SUV39H1 and HP1 in vivo by means of its pocket domain. SUV39H1 cooperates with Rb to repress the cyclin E promoter, and in fibroblasts that are disrupted for SUV39H1, the activity of the cyclin E and cyclin A2 genes are specifically elevated. The SUV39H1-HP1 complex is not only involved in heterochromatic silencing but also has a role in repression of euchromatic genes by Rb and perhaps other corepressor proteins.IP Assay Dependent
Conjugate	Biotin
Clone	HP1
Target Species	Human
Applications	IP
Supplier	Thermo Fisher Scientific
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About HP1 alpha
This gene encodes a highly conserved nonhistone protein, which is a member of the heterochromatin protein family. The protein is enriched in the heterochromatin and associated with centromeres. The protein has a single N-terminal chromodomain which can bind to histone proteins via methylated lysine residues, and a C-terminal chromo shadow-domain (CSD) which is responsible for the homodimerization and interaction with a number of chromatin-associated nonhistone proteins. The encoded product is involved in the formation of functional kinetochore through interaction with essential kinetochore proteins. The gene has a pseudogene located on chromosome 3. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Jul 2008]

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