Interactions between Barrier-to-Autointegration Factor-Like (BAF-L) and Histones

Abstract

Barrier-to-Autointegration Factor (BAF) is a conserved DNA binding protein with cellular roles in nuclear assembly, regulation of chromatin structure, and gene expression. The regulation of chromatin structure by BAF is most likely mediated through its interactions with DNA and histones. BAF is regulated through phosphorylation, but there are other potential modifications of BAF that remain unknown. Barrier-to-Autointegration Factor-Like (BAF-L) is a protein that is 40% identical and 53% similar to BAF at the amino acid level. Recombinant BAF-L can form stable homodimers and can heterodimerize with BAF in vitro and in vivo. Although BAF-L does not significantly bind to DNA and other partners of BAF, it can interact with BAF in the presence of DNA. These distinct biochemical characteristics of BAF-L suggest that it might regulate BAF function through formation of BAF/BAF-L dimers. We hypothesize that binding of BAF-L may help regulate BAF interactions with histones and DNA. Preliminary data for our research group suggests that BAF-L can, like BAF, bind to histones H1 and H3. We will confirm this preliminary finding and extend it by testing BAF-L binding to histones through several methods: far westerns, immunoprecipitations, and chromatography.