Use of DNA Photoaffinity Labeling to Study Nucleosome Remodeling by SWI/SNF

The ability of large protein assemblies to reorganize chromatin in an ATP-dependent manner is an important process for regulation of gene expression and potentially for DNA replication and recombination. The manner in which these proteins remodel chromatin to make the DNA accessible to DNA binding proteins such as transcription factors is not well understood. Site-directed DNA-protein cross-linking has been used to understand the architecture of the SWI/SNF-nucleosomal complex and the mechanistic details of how the nucleosome is remodeled. A detailed protocol for such a study is presented along with examples of the extent of this approach.