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Two related ARID family proteins are alternative subunits of human SWI/SNF complexes

Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Biochemical Journal (Impact Factor: 4.78). 11/2004; 383(Pt 2):319-25. DOI: 10.1042/BJ20040524
Source: PubMed

ABSTRACT p270 (ARID1A) is a member of the ARID family of DNA-binding proteins and a subunit of human SWI/SNF-related complexes, which use the energy generated by an integral ATPase subunit to remodel chromatin. ARID1B is an independent gene product with an open reading frame that is more than 60% identical with p270. We have generated monoclonal antibodies specific for either p270 or ARID1B to facilitate the investigation of ARID1B and its potential interaction with human SWI/SNF complexes in vivo. Immunocomplex analysis provides direct evidence that endogenous ARID1B is associated with SWI/SNF-related complexes and indicates that p270 and ARID1B, similar to the ATPase subunits BRG1 and hBRM, are alternative, mutually exclusive subunits of the complexes. The ARID-containing subunits are not specific to the ATPases. Each associates with both BRG1 and hBRM, thus increasing the number of distinct subunit combinations known to be present in cells. Analysis of the panels of cell lines indicates that ARID1B, similar to p270, has a broad tissue distribution. The ratio of p270/ARID1B in typical cells is approx. 3.5:1, and BRG1 is distributed proportionally between the two ARID subunits. Analysis of DNA-binding behaviour indicates that ARID1B binds DNA in a non-sequence-specific manner similar to p270.

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    • "ARID1A is located within chromosomal region 1p36, a region frequently deleted in a variety of human neoplastic diseases [8]. ARID1A encodes a large nuclear protein that interacts with several other proteins including either BRG or BRM, ATPases that participate in the formation of a switch/sucrose non fermentable (SMI/SNF) chromatin remodeling complex [9] [10]. BAF250a, the protein encoded by ARID1A, is one of the accessory subunits of the SWI/SNF complex. "
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    • "The protein encoded by ARID1A is a key component of the highly conserved SWI–SNF (switch/sucrose non-fermentable) chromatin remodeling complex that uses adenosine triphosphate (ATP)dependent helicase activities to allow access of transcriptional activators and repressors to DNA [Wang et al., 2004; Wilson and Roberts, 2011]. The protein therefore appears to be involved in regulating processes including DNA repair, differentiation, and development [Weissman et al., 2009]. "
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    • "Two different genes encode BAF250 proteins. BAF250A (also known as OSA1 and p270/ARID1A) is encoded by ARID1A, whereas BAF250B (OSA2) is encoded by ARID1B (Hurlstone et al., 2002; Wang et al., 2004b). In addition to the ARID domains, BAF250s also contain EHD1 and EHD2 domains, which map to the C termini and mediate protein binding (Hurlstone et al., 2002). "
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