GemininAWA does not inhibit HBO1 acetyltransferase activity. (A) GemininAWA forms a ternary complex with Cdt1 and HBO1. HA-Cdt1:FLAG-HBO1 complex was precipitated from HeLa cells expressing both proteins using anti-HA antibody. The precipitate was incubated with recombinant Geminin, and after extensive washing the amount of Geminin incorporated into the complex was determined by immunoblotting. (B) GemininAWA does not inhibit HBO1. HA-Cdt1:FLAG-HBO1 complex was purified using anti-HA antibody as in part (A), eluted with HA peptide, then incubated with acetyl coenzyme A, histone H4 peptide, and different recombinant Geminin proteins. The amount of acetylated histone H4 peptide was determined by immunoblotting.