In vivo imaging and regression analysis reveal cell-non-autonomous functions of Shroom3 during neural tube closure.

During neural tube closure, neural ectoderm cells constrict their apical surfaces to bend and fold the tissue into a tube that will become the central nervous system. These cells are physically interconnected via N-cadherin, and mutation of critical genes within relatively small numbers of cells can result in neural tube closure defects due to non-cell autonomous cell behavior defects. Despite this finding, we have a poor understanding of how neuroepithelial cells interact during apical constriction. In our previous paper, we introduced an imaging and analysis paradigm for tracking and quantifying apical constriction during neural tube closure, while also using CRISPR/Cas9 to generate mosaic loss of function of the apical constriction gene shroom3. Here we analyze the behaviors of cells along the mosaic interface of our shroom3 crispant clones, and find that Shroom3 non-cell autonomously regulates apical constriction and N-cadherin localization. Control cells along the interface constrict less, while shroom3 crispant cells along the interface constrict more. Finally, we construct a partial least squares regression (PLSR) model to estimate how both autonomous and non-cell autonomous dynamics of actin and N-cadherin affect apical surface area in both control and shroom3 crispant cells. Overall, our results demonstrate a previously unidentified non-cell autonomous role for Shroom3 in neural tube closure.