Activator‐binding domains of the SWI/SNF chromatin remodeling complex characterized in vitro are required for its recruitment to promoters in vivo

Abstract

Interaction between acidic activation domains and the activator‐binding domains of Swi1 and Snf5 of the yeast SWI/SNF chromatin remodeling complex has previously been characterized in vitro. Although deletion of both activator‐binding domains leads to phenotypes that differ from the wild‐type, their relative importance for SWI/SNF recruitment to target genes has not been investigated. In the present study, we used chromatin immunoprecipitation assays to investigate the individual and collective importance of the activator‐binding domains for SWI/SNF recruitment to genes within the GAL regulon in vivo. We also investigated the consequences of defective SWI/SNF recruitment for target gene activation. We demonstrate that deletion of both activator‐binding domains essentially abolishes galactose‐induced SWI/SNF recruitment and causes a reduction in transcriptional activation similar in magnitude to that associated with a complete loss of SWI/SNF activity. The activator‐binding domains in Swi1 and Snf5 make approximately equal contributions to the recruitment of SWI/SNF to each of the genes studied. The requirement for SWI/SNF recruitment correlates with GAL genes that are highly and rapidly induced by galactose.

Swi/Snf dynamics on stress-responsive genes is governed by competitive bromodomain interactions

“…8). Previous studies have highlighted the role of activators in regulating the recruitment and retention of the Swi/Snf complex both in vivo and in vitro (Gutierrez et al 2007;Ferreira et al 2009). Targeting of Swi/Snf by activators involves interactions of multiple subunits of Swi/Snf (including Snf2, Snf5, and Swi1) with the activator Prochasson et al 2003).…”

“…Thus, histone acetylation levels alone do not explain why significant differences in Snf2 occupancy were not observed at genes in groups 1 and 3. Transcriptional activators have been shown to play an important role in helping recruit the Swi/Snf complex along with coactivators such as SAGA (Chandy et al 2006;Ferreira et al 2009). Additionally, in vitro, a chimeric construct of VP16 activator fused to a Gal4 DNAbinding domain has been shown to target Swi/Snf specifically to activator-bound nucleosomes (Prochasson et al 2003;Gutierrez et al 2007).…”

Dominant Role for Signal Transduction in the Transcriptional Memory of Yeast GAL Genes

“…on May 12, 2018 by guest http://mcb.asm.org/ (10). Presumably, these strain backgrounds have a higher level of basal Gal3 signaling (or lower levels of the Gal80 repressor).…”

Chromatin and Transcription in Yeast

“…Recruitment likely occurs by direct interaction with transcriptional activators (Yudkovsky et al 1999). As several different activators can recruit Swi/Snf, the nature of the activator-Swi/Snf interaction is of interest; studies have shown that two or three Swi/Snf subunits can participate in recruitment (Neely et al 2002;Prochasson et al 2003;Ferreira et al 2009). Once at a promoter, the association of Swi/Snf is stabilized by the Snf2 bromodomain (Hassan et al 2001(Hassan et al , 2002, which binds acetylated histone tails (Dhalluin et al 1999); this represents an example of cooperation between Gcn5 histone acetylation and Swi/Snf and is consistent with reports that Swi/Snf association is Gcn5 dependent (Govind et al 2005;Mitra et al 2006).…”