Figure S4.

Midgut migration and repolarization is perturbed in zygotic mutants for the CopII trafficking pathway.(a) In wild-type embryos, the anterior midgut and posterior midgut have met and fused by stage 13, and the ICPs sit in the middle (a, arrow, asterisks). (b) In mutants for sec16, midgut migration is delayed, and gaps are seen between the anterior and posterior midgut rudiments (arrowhead). ICP migration is also perturbed, and they are found more posteriorly than in wild type (b, arrow, asterisks). (c) In sec23 mutants, the midgut cells show defects similar to other CopII pathway zygotic mutants; there are gaps in the midgut (arrowhead), and the ICPs are found more posteriorly than in wild type (c, arrow, asterisks). (d and e) Midgut cells in stage 15 sar1 mutant embryos. (f) Plots of the average fluorescence intensity (represented as mean gray value) of Baz, E-Cad, and βPS in stage 15 midgut cells mutant for sar1 measured along the apical (A) to basal (B) axis of a cell (represented in e by red line). Each n represents the average of 10 cells measured in one embryo (black lines). n = 6 per condition; the mean for each condition is plotted in red. White dashed lines in a and b indicate the apical side of the midgut, and yellow lines, the basal. Scale bars, 50 µm (a–c) and 10 µm (d and e).