Nucleosome Transactions on the Promoters of the YeastGAL and PHO Genes

The GAL and PHO genes of yeast provided some of the earliest evidence for specific nucleosome changes on eukaryotic promoter regions, and they continue to contribute unique insights to this emerging area. These nutrient-regulated systems possess major advantages for chromatin studies. Gene activity is tightly regulated and easily manipulated; firm genetic foundations provide strong functional correspondence for biochemical analyses. The promoter region nucleosome changes (舠transactions舡) to be discussed here include disruption, which refers to the loss of nucleosome structure observed when transcription is activated, andreorganization, which refers to the regeneration of promoter region nucleosome structure and is associated with gene inactivation.