Chromo/chromo shadow domain
IPR000953
Definition
The CHROMO (CHRromatin Organization MOdifier) domain [[cite:PMID:1982376], [cite:PMID:1708124], [cite:PMID:7667093], [cite:PMID:7501439]] is a conserved region of around 60 amino acids, originally identified in Drosophila modifiers of variegation. These are proteins that alter the structure of chromatin to the condensed morphology of heterochromatin, a cytologically visible condition where gene expression is repressed. In one of these proteins, Polycomb, the chromo domain has been shown to be important for chromatin targeting. Proteins that contain a chromo domain appear to fall into 3 classes. The first class includes proteins having an N-terminal chromo domain followed by a region termed the chromo shadow domain, with weak but significant sequence similarity to the N-terminal chromo domain PMID:7667093, eg. Drosophila and human heterochromatin protein Su(var)205 (HP1). The second class includes proteins with a single chromo domain, eg. Drosophila protein Polycomb (Pc); mammalian modifier 3; human Mi-2 autoantigen and several yeast and Caenorhabditis elegans hypothetical proteins. In the third class paired tandem chromo domains are found, eg. in mammalian DNA-binding/helicase proteins CHD-1 to CHD-4 and yeast protein CHD1. Functional dissections of chromo domain proteins suggests a mechanistic role for chromo domains in targeting chromo domain proteins to specific regions of the nucleus. The mechanism of targeting may involve protein-protein and/or protein/nucleic acid interactions. Hence, several line of evidence show that the HP1 chromo domain is a methyl-specific histone binding module, whereas the chromo domain of two protein components of the drosophila dosage compensation complex, MSL3 and MOF, contain chromo domains that bind to RNA in vitro PMID:11574148. The high resolution structures of HP1-family protein chromo and chromo shadow domain reveal a conserved chromo domain fold motif consisting of three β-strands packed against an α-helix. The chromo domain fold belongs to the OB (oligonucleotide/oligosaccharide binding)-fold class found in a variety of prokaryotic and eukaryotic nucleic acid binding protein PMID:11574148.
30 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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