TAP-fused proteins were detected by an antibody against the protein A portion of the TAP tag. Total proteins from cell cultures overexpressing the TAP-fused target proteins (marked on the top) were separated by SDS-PAGE and analyzed by western blots. The protein sizes are labeled to the left side of each gel (kD). The molecular masses (kD) of the target proteins are as follows: AtCPSF30, 29; AtCPSF73-I, 78; AtCPSF73-II, 69; AtCPSF100, 83; AtCLPS3, 48; and AtFY, 73.