Variations in the composition of mammalian SWI/SNF chromatin remodelling complexes

Jessica Ryme, Patrik Asp, Stefanie Böhm, Erica Cavellán, Ann Kristin Östlund Farrants

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

The ATP-dependent chromatin remodelling complexes SWI/SNF alter the chromatin structure in transcriptional regulation. Several classes of mammalian SWI/SNF complex have been isolated biochemically, distinguished by a few specific subunits, such as the BAF-specific BAF250A, BAF250B and BRM, and the PBAF-specific BAF180. We have determined the complex compositions using low stringency immunoprecipitation (IP) and shown that the pattern of subunit interactions was more diverse than previously defined classes had predicted. The subunit association at five gene promoters that depend on the SWI/SNF activity varied and the sequential chromatin immunoprecipitations revealed that different class-specific subunits occupied the promoters at the same time. The low-stringency IP showed that the BAF-specific BAF250A and BAF250B and the PBAF-specific BAF180 co-exist in a subset of SWI/SNF complexes, and fractionation of nuclear extract on size-exclusion chromatography demonstrated that sub-complexes with unorthodox subunit compositions were present in the cell. We propose a model in which the constellations of SWI/SNF complexes are "tailored" for each specific chromatin target and depend on the local chromatin environment to which complexes and sub-complexes are recruited.

Original languageEnglish (US)
Pages (from-to)565-576
Number of pages12
JournalJournal of Cellular Biochemistry
Volume108
Issue number3
DOIs
StatePublished - Oct 15 2009
Externally publishedYes

Keywords

  • BAF proteins
  • BRG1
  • BRM
  • Chromatin remodelling

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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