a) 293A cells were transfected with the indicated combinations of pcDNA, HA-TIP60 and GFP-DMAP1. After 48 hours cells were harvested, and lysates immunoprecipitated using either an HA antibody or Ig control. Inputs and immunoprecipitates were immunoblotted for HA and GFP. Two different exposures of the HA immunoblot are shown. For (b), (c) and (d) cells were transfected with the indicated combinations of pcDNA, Myc-DMAP1, HA-TIP60, siControl and siTIP60. After 48 hours lysates were immunoprecipitated with either HA antibody, Myc antibody or Ig control. Washed immunoprecipitates were incubated with a colourimetric histone substrate, and HAT activity determined by spectrophotometry. Machine background was subtracted, and experimental values were normalised to a reaction containing no immunoprecipitate. The p-value of three independent experiments was calculated using the student’s t-test (*p<0.05).