1. Division of Basic Sciences, The Fred Hutchinson Cancer Research Center, and Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98109, USA
2. The Howard Hughes Medical Institute , Seattle, Washington 98109, USA
3. Present address: Institute for Systems Biology, Seattle, Washington 98105, USA.

Correspondence to: Steven Hahn^1,3 Correspondence and requests for materials should be addressed to S.H. (e-mail: Email: shahn@fhcrc.org).

Abstract

High levels of gene transcription by RNA polymerase II depend on high rates of transcription initiation and reinitiation. Initiation requires recruitment of the complete transcription machinery to a promoter, a process facilitated by activators and chromatin remodelling factors. Reinitiation probably occurs through a different pathway¹. After initiation, a subset of the transcription machinery remains at the promoter, forming a platform for assembly of a second transcription complex^{2, 3, 4}. Here we describe the isolation of a reinitiation intermediate that includes transcription factors TFIID, TFIIA, TFIIH, TFIIE and Mediator. This intermediate can act as a scaffold for formation of a functional reinitiation complex. Formation of this scaffold is dependent on ATP and TFIIH. The scaffold is stabilized in the presence of the activator Gal4–VP16, but not Gal4–AH, suggesting a new role for some activators and Mediator in promoting high levels of transcription.