Puffing and Histone Acetylation in Polytene Chromosomes

Abstract
Fixation with picric acid or formaldehyde retains incorporated [3H]acetate which is lost after fixation with ethanol and acetic acid. Unlike [3H]uridine, [3H]acetate is diffusely incorporated into polytene chromosomes, and not preferentially into existing or newly induced puffs. It is suggested that puff formation does not include an acetylation of histones.