| ARID | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 human mrf-2 domain, nmr, 11 structures | |||||||||
| Identifiers | |||||||||
| Symbol | ARID | ||||||||
| Pfam | PF01388 | ||||||||
| InterPro | IPR001606 | ||||||||
| SCOP2 | 1ig6 /SCOPe /SUPFAM | ||||||||
| |||||||||
Inmolecular biology, theARID domain (AT-rich interaction domain; also known as BRIGHT (B-cellRegulator ofIgHeavy chainTranscription) domain[1]))[2] is aprotein domain that binds toDNA. ARID domain-containing proteins are found infungi, plants[3] andinvertebrate andvertebratemetazoans. ARID-encodinggenes are involved in a variety ofbiological processes including embryonic development,cell lineagegene regulation andcell cycle control. Although the specific roles of this domain and of ARID-containingproteins intranscriptional regulation are yet to be elucidated, they include both positive and negativetranscriptionalregulation and a likely involvement in the modification ofchromatin structure.[4] The basic structure of the ARID domain appears to be a series of sixalpha-helices separated bybeta-strands, loops, or turns, but the structured region may extend to an additionalhelix at either or both ends of the basic six. Based on primarysequence homology, they can be partitioned into threestructural classes: Minimal ARIDproteins that consist of a core domain formed by six alpha helices; ARID proteins that supplement the core domain with an N-terminal alpha-helix; and Extended-ARID proteins, which contain the core domain and additionalalpha-helices at their N- and C-termini.
The humanSWI-SNF complex proteinARID1A is an ARID family member with non-sequence-specific DNAbinding activity. The ARID consensus and other structural features are common to both ARID1A andyeast SWI1, suggesting that ARID1A is ahuman counterpart of SWI1.[5] The approximately 100-residue ARIDsequence is present in a series of proteins strongly implicated in the regulation ofcell growth, development, and tissue-specificgene expression. Although about a dozen ARID proteins can be identified from database searches, to date, only Bright (a regulator of B-cell-specificgene expression), dead ringer (aDrosophila melanogaster geneproduct required for normal development), and MRF-2 (which repressesexpression from theCytomegalovirus enhancer) have been analyzed directly with regard to their DNA binding properties. Eachbinds preferentially to AT-rich sites. In contrast, ARID1A shows nosequence preference in its DNA binding activity, thereby demonstrating that AT-rich binding is not an intrinsic property of ARIDdomains and that ARID family proteins may be involved in a wider range of DNA interactions.[5]