Fig. 5.

A) (top): Design of single molecule assay for detecting retention of σ⁷⁰ during elongation; (bottom): images of the same microscope field of view of AF488–DNA (blue), Cy5–σ⁷⁰ (red), and transcript-hybridization probe (green) taken at the specified times. B) (top): Two examples of time records of transcript probe (green) and σ⁷⁰ (red) fluorescence, each colocalized at a DNA spot σ⁷⁰ fluorescence departs before the time interval (shaded) during which transcript probe fluorescence is present. (bottom) σ⁷⁰ fluorescence persists throughout transcript probe interval. (C) The fraction (± SEM) of TECs that retain σ⁷⁰ at the time transcript probe is first detected on the TEC (reprinted from Harden et al, PNAS, 2016 [81]; used with permission).