FIG. 1.

Two distinct type A HAT activities exist in Tetrahymena macronuclei. (A) Sucrose-gradient sedimentation of HAT activities characterized with either a mixture of free (nonnucleosomal) histones (peak I) or nucleosomal histones (peak II); histone substrates were from chickens. (B) Western blot analysis using yAda1p and yAda5p/ySpt20p antisera as well as Tetrahymena p55 (K36) peptide antibodies. (C) Acetylated histone products were examined following gel electrophoresis and fluorography. Lanes C contain DNase I extract as input.