Figure 5.

Visualization of arrested RNA pol II by immunoblotting. Lane 1, 5% of the nuclear extract present in the transcription reaction. Transcription was performed with unbound template in the presence of beads: lane 2, buffer D wash of beads; lane 3, beads treated with SDS loading buffer. P15 (10 μM) was used to form triplex and UV irradiated, and this template was immobilized on magnetic beads and used for transcription. Bound RNA pol II complexes were separated by magnet: buffer D wash (lane 4) and beads treated with SDS loading buffer (lane 5). RNA pol II (Pol IIa, unphosphorylated form; Pol IIo, phosphorylated form) is shown.