Figure 4.

CRSP elutes before the protein peak from the Ni²⁺-NTA-agarose. (a) Reconstituted transcription reactions with GC box template, Sp1, RNA polymerase II and basal factor fractions, and IP-TFIID (lanes 1–8) supplemented with input fraction (lane 2), flow-through fraction (FT) (lane 3), or various elution fractions from Ni²⁺-NTA-agarose chromatography (lanes 4–8). Transcription from a GC box template and a control DNA template lacking Sp1 binding sites is indicated by filled and open arrowheads (b) Silver-stained SDS/PAGE gel of various Ni²⁺ eluate fractions. Molecular size standards are shown on the left. (c) Silver-stained SDS/PAGE gel of CRSP fraction derived from MonoS chromatography directly after the Ni²⁺-NTA-agarose step. Molecular size standards are shown on the left, and the apparent molecular weight of the CRSP subunits are listed on the right. ∗ indicate contaminating polypeptides present in this preparation that do not represent CRSP subunits.