Chromatin Remodeling: Chromo Domain

Chromodomain of HP1 bound to methylated histone H3-K9.

Domain Binding and Function

The Chromatin Organization Modifier (Chromo) domain is defined as a 30–70 amino acid residue protein module found in many proteins involved in the assembly of protein complexes on chromatin. This domain was first described in Drosophila modifiers of variegation proteins that modify chromatin into condensed heterochromatin, a cytologically visible region of repressed gene expression. Examples of Chromo-domain-containing proteins include transcriptional repressors HP1 and Polycomb (Pc), and the human retinoblastoma binding protein (RBP-1). Chromo domains promote protein binding to methylated lysines in the tail region of histone H3. Chromo domains can function individually or in tandem, as with CHD1, to recognize specific methylated Histone tails.

Structure Reference

  1. Jacobs, S.A. et al. (2002) Science 295,2080–2083.

Examples of Domain Proteins

Chromatin Remodeling: Chromo Domain

Binding Examples

Chromodomain Proteins Binding partners
HP1 Histone H3 methylated lysine-9
Polycomb Proteins Histone H3 methylated lysine-27
CHD1 Histone H3 methylated lysine-4