Mutual Inactivation of Notch Receptors and Ligands Facilitates Developmental Patterning
(A) Notch reporter profiles (green heat map, bottom panel) for varying maximal production rates of DSL, (red curves in top panel) and a fixed production rate of Notch, (blueline). Spatially-uniform reduction in levels (y-axis, lower panel) results in restriction of the vein to a progressively narrower region (lower panel). However, when the DSL production rate is lowered to the extreme when everywhere, all cells are in receiver states, and vein boundaries are no longer restricted by Notch signaling (see discussion in text). This is the expected behavior in the Delta+/− heterozygous mutant when the DSL production rate is half that of the wild-type (arrows), if in the wild type . (B) The Notch reporter profile is sensitive to intrinsic (uncorrelated) noise but robust to extrinsic (correlated) noise in Notch and DSL production rates. Simulations of boundary formation with static multiplicative production rate noise of similar magnitude but different degrees of correlation (blue scatter plots) show that the pattern is less sensitive to extrinsic noise (top) than intrinsic noise (bottom). (C) The effect of noise amplitude and degree of correlation on Notch reporter peak positions. Standard deviation in peak position (color bar) at each row (red dots in B) is calculated from 300 simulations of 8×24 cell arrays (such as those in B) for different noise attributes. The noise parameters used in B are marked (white circles). See Supporting Information Text S1.5 and Table S1 for parameter values and description of noise generation.