Chromodomain
A chromodomain is a protein domain, the first in the Drosophila melanogaster proteins Polycomb (Pc) and heterochromatin protein 1 ( HP1 ) was identified.
The role of this domain in Drosophila is probably the transport and binding of Pc and HP1 to the heterochromatin and other chromatin components. Thus Chromodomänen play a role in chromatin remodeling and the formation of heterochromatin regions, especially in the shutting down of genes, the so -called " epigenetic silencing" or " gene silencing ". Chromodomänen recognize and bind N- termini, which have methylated lysines. The chromodomain Pc binds to the methylated histone H3K27 ( histone 3 lysine 27), the HP1 chromodomain to the di - and trimethylated histone H3K9 ( histone 3 lysine 9). Chromodomänen are a component of the RNA-induced transcriptional silencing complex ( RITS complex).
Known proteins are Chromodomänen HP1, Polycomb, the histone methyltransferase Suv (3 ) 9, the helicase CHD and the retinoblastoma - binding protein 1 ( RBP1 ).