Repressed PHO5 gene chromatin, isolated from yeast in the native state, was 
remodeled by yeast extract in a gene activator-dependent, ATP-dependent manner. 
The product of the reaction bore the hallmark of the process in vivo, the 
selective removal of promoter nucleosomes, without effect on open reading frame 
nucleosomes. Fractionation of the extract identified a single protein, 
chromodomain helicase DNA binding protein 1 (Chd1), capable of the remodeling 
activity. Deletion of the CHD1 gene in an isw1Δ pho80Δ strain abolished PHO5 
gene expression, demonstrating the relevance of the remodeling reaction in vitro 
to the process in vivo.