Extended Data Figure 2: Schematic diagram showing assembly of dumbbells, in cross-section.
From: Real-time observation of the initiation of RNA polymerase II transcription

PICs were attached to one bead via biotin-avidin linkages (yellow). To form dumbbell tethers, the other end of a small fraction of the PICs (4%) had digoxigenin linkages that could be tethered to anti-digoxigenin-coated beads (black and brown) via a 2.7-kb DNA handle. PICs not involved in tether formation served to increase the local concentration of PIC components.