Fig. 1. Brain Organoid development and wrinkling.

(a) Illustration of the two-dimensional compartment, h = 150μm. The top membrane is coupled to a media reservoir, and the bottom coverslip enables in situ imaging. (b) Z-stack image of the organoid showing actin using Lifeact-GFP (green) and cell nuclei using H2B-mCherry (red). (c) Illustration of an organoid optical section. (d) Fluorescence image and illustration showing cell organization in the organoid. Dashed white line marks inner organoid surface surrounding a lumen. Cells exhibit a bi-polar morphology, stretched between the outer surface (r = t) and the inner surface (r = 0). Nuclei are distributed along the radial coordinate, and cell division occurs at the inner surface (r = 0). (e) Fluorescence images showing the development of the organoid during days 3-11 after Matrigel embedment, and the emergence of wrinkles. Arrows indicate initial wrinkling instability. (f) RNA sequencing expression data in the organoids for three developmental time points: embryonic stem cell culture, organoids 5 and 12 days after Matrigel embedment. Six samples are shown for each time point (3 wild-type, 3 LIS1 +/− mutants). Color bar indicates the row z-score. The list contains genes that are typical for telencephalon and cortical brain regions. Scale bars are 100μm (e), 50μm (b), 20μm (d). Error bars represent s.e.m.