PDCD5 interacts with HAM1/HAM2 and participates in the same UV-B DNA damage response pathway. A, Relative CPD accumulation in the pdcd5-2 mutant, ham1ham2  RNAi, and ham1ham2  RNAi/pdcd5 plants versus wild-type (WT) plants immediately after a 4-h UV-B treatment under conditions that allowed photorepair in the light. B, Nuclear protein extracts from transgenic plants expressing Pro_35S:AtPDCD5-GFP were used for coimmunoprecipitation (IP) experiments using anti-GFP antibodies (lane 1). As a negative control, a nuclear protein extract from wild-type Col-0 plants was incubated with anti-GFP antibodies (lane 3). Also, 30 μg of total nuclear protein extract before coimmunoprecipitation was included as a positive control (lane 2). Western blots were developed using anti-TIP60 antibodies (HAM1/HAM2). C, Nuclear protein extracts from transgenic plants expressing Pro_35S:AtPDCD5-GFP were incubated with purified recombinant GST-AtHAM2 fusion protein and were used in pull-down experiments using anti-GST antibodies (5 μg; lane 1). As negative controls, nuclear extracts from transgenic plants were incubated with GST protein (5 μg; lane 2), and nuclear extracts from wild-type Col-0 plants were incubated with either GST-AtHAM2 (lane 3) or GST (lane 4). Western blots were developed using anti-GFP antibodies. Thirty micrograms of total nuclear protein extract before coimmunoprecipitation was included as a positive control (input). Prestained molecular weight markers (MWM) and their corresponding molecular masses are included at the left side of each gel.