Fig. 2

JellyOp allows time-dependent manipulation of the circadian clock. a JellyOp-expressing per2::luc rat1 fibroblasts (black squares and line) show a robust increase in luminescent cAMP reporter activity following exposure to light, which is absent in cells expressing only the GloSensor reporter (grey squares and line). The data present representative traces of baseline normalised luminescence units (mean ± SEM) from triplicate samples in a single assay. Cells were pulsed with single light flashes at 2 and 12 min, followed by 30 light flashes (at 30 second intervals) starting at 22 min, indicated by grey arrows. b The circadian luciferase rhythm of per2::luc (on the left) and JellyOp-expressing per2::luc (on the right) rat1 fibroblasts exposed to 4 h of intermittent white light (28.40 mW cm^–2) at various phases of the per2 rhythm (indicated by arrows: at CT11.2, CT2.1, CT17.3 for per2::luc and at CT11.8, CT3.1, CT19.6 for JellyOp per2::luc). For phase analysis, baseline corrected bioluminescence rhythms prior to light treatment were modelled by a sine wave (grey dotted line). Time of first trough in per2::luc rhythm aligned for all traces to facilitate comparisons. c Phase response profile for JellyOp-expressing per2::luc rat1 fibroblasts illustrates the relationship between the timing of light onset and magnitude of phase shifts in per2 rhythm. Data represent the extent of phase shifts captured from individual light pulsed cultures and plotted on a y-axis where positive and negative values denote phase advances and delays, respectively (values are reported in Additional file 1)