Fig. 5: Snail repressor introduces a second non-productive state and modulates promoter state switching rates.
a Schematic of the sna distal enhancer transgene with the ‘core’ enhancer module49 (blue) and Snail binding sites (pink) indicated. Enhancer transgene schematics for the snailDistal enhancer (b), snailDistalAlt with mutated Sna binding sites (c), snailDistalMut with mutated Sna binding sites (d) and snailDistalCore with the ‘core’ enhancer module only (e). Heatmap showing the number of polymerase initiation events in nc14 for snailDistal (f), snailDistalAlt (g), snailDistalMut (h) and snailDistalCore (i) as a function of time. Each row represents one nucleus, and the number of Pol II initiation events per 30 s bin is indicated by the bin color. J Topology of the three-state kinetic model with non-sequential OFF1 and OFF2 states. Representation of estimated bursting dynamics for snailDistal (k), snailDistalAlt (l), snailDistalMut (m) and snailDistalCore (n). Permissive ON state durations are depicted in green and inactive OFF states in red and orange, and probabilities of each state shown above. Statistics: snailDistal N = 3 embryos, n = 224 nuclei; snailDistalAlt N = 5 embryos, n = 220 embryos; snailDistalMut N = 2 embryos, n = 145 nuclei; snailDistalCore N = 3 embryos, N = 194 nuclei. See Supplementary Movies 4–7.
