TAF7: traffic controller in transcription initiation

Abstract

TAF7, a component of the TFIID complex, controls the first steps of transcription. It interacts with and regulates the enzymatic activities of transcription factors that regulate RNA polymerase II progression. Its diverse functions in transcription initiation are consistent with its essential role in cell proliferation.

Keywords: T cells; TAF7; differentiation; proliferation; transcriptional regulation.

Figure 1. TAF7 is a traffic controller of transcription initiation. Schematic representation of TAF7 functions in the early steps of transcription. Before initiation of transcription, TAF7 binds TAF1 and inhibits its AT activity (red lightning bolt) which prevents premature initiation. TAF7 then sequentially regulates TFIIH, Brd4 and p-TEFb, inhibiting each of their kinases activities which blocks CTD phosphorylation and progression of the polymerase. The release of TAF7 from TAF1 and from the CTD kinases allows the RNAP II machinery to move forward. The events inhibited by TAF7, the transcription steps and the positions of the polymerase where they occur are indicated below the schema.