Figure 4.

(a) In vivo-labeled CDK7 immunoprecipitated from affinity purified TFIIH and analyzed by Western blot (bottom) after autoradiography (top). (=) The resolved shift in the mobility of mitotic CDK7. (b). (Top) Basal transcription from the AdML promoter was reconstituted with affinity purified interphase TFIIH (lane 2), mitotic TFIIH (lane 3), mitotic or interphase TFIIH pretreated with alkaline phosphatase in the absence or presence of sodium phosphate as indicated. (Lane 1) The result using a mock affinity purification procedure. (Bottom) Western blot analysis of the samples analyzed in transcription at top using anti-CDK7 antibodies.