FIG. 2. Biophysical properties of Bcd clusters.

(A) A single nucleus showing Bcd-GFP heterogeneities. Close-up image (right) shows a single Bcd-GFP cluster. Cluster intensity fit with a 2D Gaussian (see profile below). The cluster intensity $\left(I_c\right)$, the cluster background intensity $\left(I_{\mathrm{b}\mathrm{g}}\right)$, and the linear cluster size $d$ are extracted from this fit (Methods). (B) A histogram of the signal-to-noise ratio ($I_c/I_{\mathrm{b}\mathrm{g}}$) and (C) a histogram of the linear size $\left(d\right)$ for 99671 clusters from 2027 nuclei in 14 embryos expressing Bcd-GFP. (D) Number of clusters per nucleus as a function of average nuclear Bcd-GFP intensity (mean ± std). (E) Average cluster intensity per nucleus as a function of average nuclear Bcd-GFP intensity (mean ± std). (F) Effective cluster diameter $\left(d\right)$ as a function of average nuclear intensity.