Chromatin remodeling
	the role of chromatin remodeling is complex and requires additional proteins and energy, but is essential for gene expression nucleosomal organization is generally hostile to transcription SWI/SNF complex is a large protein (2M daltons), 150/cell, that interacts with at least some transcription factors (e.g. GAL4) acetylation of histone tails may also play an important role--heterochromatin tends to be underacetylated