Structure and oligomeric state of human transcription factor TFIIE

The general RNA polymerase II transcription factor TFIIE, which is composed of two subunits, has essential roles in both transcription initiation and promoter escape. Electron microscopy analysis of negatively stained human TFIIE showed a large proportion of α/β heterodimers as well as a small proportion of tetramers. Analytical ultracentrifugation, chemical crosslinking, pulldown experiments and cryo-electron microscopy confirmed that TFIIE is a α/β heterodimer in solution. Three-dimensional envelopes of the α/β particles showed an elongated structure composed of three distinct modules. Finally, a model for the quaternary architecture of the complex is proposed that provides a structural framework to discuss the function of TFIIE in the context of RNA polymerase II transcription initiation