Figure 1. Crb persists during early NB... | Rockefeller University Press

Figure 1.

$Crb persists during early NB ingression and undergoes rapid removal during late ingression. (A) Schematic of gastrulating Drosophila embryo (stage 8) when S1 NBs ingress. (B) Apical surface of ingressing live NBs (yellow dots or arrowheads) expressing endo-Crb::GFP or endo-Ecad::GFP. Time after onset of ingression. Scale bars, 5 μm. (C and D) Junctional Crb::GFP and Ecad::GFP fluorescence (average pixel intensity at cell boundaries; C) and total apical protein levels (fluorescence intensity per cell; D). Blue lines represent average apical area. 58 NBs, 12 embryos for endo-Crb::GFP, and 30 NBs, 6 embryos for endo-Ecad::GFP. T = 0 min, the onset of ingression. Error bars are SEM. (E) Apical perimeter and total apical Crb::GFP during ingression (upper panel; T = 0 min, onset of ingression) and fraction of change in apical perimeter and total Crb::GFP during ingression of a representative NB. Apical Crb levels decrease (rate <0) during apical contractions and increase (rate >0) during apical expansions. Apical Crb losses overtake gains during late ingression. (F) Scatter plot showing the relationship between the fraction of perimeter change during apical contractions or expansions and the corresponding fraction of total apical Crb change (relative Crb increase or decrease). N values as in Fig. S1 A. (G) Schematic interpretation of data in F illustrating preferential Crb membrane removal during cell contraction and re-insertion during apical surface expansion.$

Crb persists during early NB ingression and undergoes rapid removal during late ingression. (A) Schematic of gastrulating Drosophila embryo (stage 8) when S1 NBs ingress. (B) Apical surface of ingressing live NBs (yellow dots or arrowheads) expressing endo-Crb::GFP or endo-Ecad::GFP. Time after onset of ingression. Scale bars, 5 μm. (C and D) Junctional Crb::GFP and Ecad::GFP fluorescence (average pixel intensity at cell boundaries; C) and total apical protein levels (fluorescence intensity per cell; D). Blue lines represent average apical area. 58 NBs, 12 embryos for endo-Crb::GFP, and 30 NBs, 6 embryos for endo-Ecad::GFP. T = 0 min, the onset of ingression. Error bars are SEM. (E) Apical perimeter and total apical Crb::GFP during ingression (upper panel; T = 0 min, onset of ingression) and fraction of change in apical perimeter and total Crb::GFP during ingression of a representative NB. Apical Crb levels decrease (rate <0) during apical contractions and increase (rate >0) during apical expansions. Apical Crb losses overtake gains during late ingression. (F) Scatter plot showing the relationship between the fraction of perimeter change during apical contractions or expansions and the corresponding fraction of total apical Crb change (relative Crb increase or decrease). N values as in Fig. S1 A. (G) Schematic interpretation of data in F illustrating preferential Crb membrane removal during cell contraction and re-insertion during apical surface expansion.