Figure 2. RA gradients are noisy in space and time.

(A, B) Spatial noise. Plots show relative abundance of RA in five parallel rows of cells (each color corresponds to a different row) along the A-P axis of the neural ectoderm within a single embryo. (A) Experimental – each point represents the integrated signal of 40 consecutive FLIM measurements (2.7 min) (solid line represents best fit). (B) Computational – line represents the mean of 500 model simulations. (C, D) Temporal noise. Graphs show variability in relative abundance of RA in five single cells (each color corresponds to a different cell) at equivalent A-P positions over time. (C) Experimental – FLIM measurements were taken every 12 s. (D) Computational – colors correspond to individual cells for each stochastic realization. See also Supplementary file 1.

DOI: http://dx.doi.org/10.7554/eLife.14034.006

Figure 2—figure supplement 1. Instrument noise cannot account for noise in phasor-FLIM measurements of RA.

Comparison of temporal noise in FLIM measurements of three different solutions (fluorescein in aqueous KOH, pH 9.0, rhodamine in water and RA in DMSO) and single cells in 9 different wildtype (WT) embryos. The graph represents the deviation from the mean position on the phasor plot for the solutions and the deviation from the mean abundance of RA for the cells. Each point corresponds to values at a single time point and the lines represent the mean and standard deviation. The variability in the measurements from cells is larger than those for solutions and vastly exceeds the maximum theoretical uncertainty due to photon shot noise.

DOI: http://dx.doi.org/10.7554/eLife.14034.007