Fig. 1. SAP130 is a component of the TFTC complex. (A) A 50 µg aliquot of HeLa cell nuclear extract (NE; lane 1), 15 µl of immuno purified and eluted SAP130 from HeLa NE [E(IPSAP130); lane 2], 15 µl of immunopurified TFTC (lane 3) and TFIIDβ (lane 4) were separated by SDS–PAGE, blotted on a nitrocellulose filter and examined for the presence of the indicated proteins using the corresponding antibodies. (B) TFTC (lane 1, and see C) was re-immunoprecipitated (IP) with either an anti-TAF_II135 mAb (lane 2) or an anti-hSPT3 mAb (lane 3), the mAb–protein G-bound proteins were washed extensively, separated by SDS–PAGE, blotted on a nitrocellulose filter and examined for the presence of the indicated proteins by using the corresponding antibodies. (C) A 15 µl aliquot of TFTC was separated by SDS–PAGE and analysed by silver staining.