The actin-related protein Arp6 contributes to chromatin anchoring independently of its nucleosome remodeling activity

The SWR1 chromatin remodeling complex, which contains Arp6 and Swr1 as components, exchanges H2A in nucleosomes with its variant H2AZ. We have investigated the chromosome-wide dynamic distribution of Arp6 and Swr1 in budding yeast cells by chromatin immunoprecipitation analysis using a high-density genome tiling array. We found that the majority of Arp6 colocalizes with Swr1 on chromosomes and is enriched in the promoters of divergently promoters. This shows that Arp6 binds chromatin as a component of the SWR1 complex and is involved in transcriptional regulation in these regions. On the other hand, in some chromosomal regions, including telomere, centromere and ribosomal protein genes, the binding of Arp6 did not coincide with that of Swr1, and was remained in the absence of Swr1. This shows that a portion of Arp6 binds to chromosomes in Swr1-independent manner. These observations suggest that Arp6 has Swr1-dependent and –independent functions on chromosomes. Keywords: ChIP-chip ･ The goal of the experiment. Genome-wide localization of Arp6, Swr1 in Wt and Arp6 in swr1 deleted cells on chromosomes in Saccharomyces cerevisiae ･Key word Saccharomyces cerevisiae, Genome tilling array (chromosome III, IV, V, VI), Arp6, Swr1 ･Experimental factor Distribution of Arp6 and Swr1in WT cells in random culture. Distribution of Arp6 in swr1 delta cells in random culture. ･ Experimental design ChIP analyses: W303 background cells expressing FLAG tagged protein were used for the ChIP using anti-FLAG M2 antibody. ChIP-chip analyses: In all cases, hybridization data for ChIP fraction was compared with WCE (whole cell extract) fraction. Saccharomyces cerevisiae affymetrix genome tiling array (SC3456a520015F for chromosome III, IV, V, VI ) was used.