A single-molecule optical tweezer assay is developed to monitor transcription initiation in eukaryotic RNA polymerase II in real-time, making use of a highly purified preinitiation complex (PIC) from yeast; observations show that a large bubble is opened up in the DNA template during initiation, driven by the TFIIH helicase that forms part of the PIC, along with synthesis of an extended transcript before the transition from transcription initiation into elongation.
- Furqan M. Fazal
- Cong A. Meng
- Steven M. Block
