Figure 2.

(A) XZ slices appear flat and boundary angles are steady during motion. (B) Intensity traces along the z axis are fit at 1000 locations over 2.4 h (one location and time shown; red line, fit). (C) The overlay of intensity at one location over time shows small variations. (D) The overlay of the space-averaged traces also shows small variations. (E) Layer thickness averaged over space and time is 7.1 ± 0.7 μm. (F) Z projections show clear boundaries. (G) Boundary angles are determined from XZ slices. (H) Boundaries maintain constant orientation (each dataset is for a different boundary). (I and J) Angle histogram and cumulative distribution function show that 73% of cell boundaries are oriented within 45° of vertical. (Scale bars = 50 μm; all XZ plots have the same scale along both directions.) To see this figure in color, go online.