Vibe, C. | Search bioRxiv

bioRxiv2025

De novo E-cadherin/catenin complex formation controls basal epithelial mechanics and force transmission for apoptotic cell clearance

Beyond serving as cohesive barriers, epithelia clear apoptotic cells to regulate development, homeostasis and inflammation. How epithelial cells remodel their shape during phagocytosis while preserving tissue integrity, and the role of adhesion receptors in this process, remain unclear. Using live in vivo imaging of phagocyte-target interactions in zebrafish (Danio rerio) embryos, we show that basal and apical epithelial domains are mechanically decoupled, enabling engulfment without disrupting tissue cohesion. We identify a dynamic assembly of E-cadherin/catenin complexes at the basal epithelial surface in contact with apoptotic cells. Targeted perturbations reveal two critical functions of de novo E-cadherin/catenin complex formation at the phagocytic synapse: -catenin acts as a physical linker transmitting actin-generated forces required for engulfment, while p120-catenin restrains Myosin II activity, enabling efficient clearance. We further demonstrate the conservation of E-cadherin-dependent apoptotic cell clearance in the mouse trophectoderm. These findings reveal that the E-cadherin/catenin complex is repurposed at the phagocytic synapse as a mechano-regulator of epithelial efferocytosis beyond its canonical role in tissue cohesion.

cell biology↗

bioRxiv2023

Modular control of time and space during vertebrate axis segmentation

How temporal and spatial control of developmental processes are linked remains a fundamental question. Do underlying mechanisms form a single functional unit or are these dissociable modules? We address this question by studying the periodic process of embryonic axis segmentation, using genetic crosses of inbred medaka fish strains representing two species, Oryzias sakaizumii and latipes. Our analysis revealed correlated interspecies differences with regard to the timing of segmentation, the size of segments and of the presomitic mesoderm (PSM), from which segments are periodically formed. We then did interspecies crosses and real-time imaging quantifications, which revealed extensive phenotypic variation in [~]600 F2 embryos. Importantly, while the F2 analysis showed correlated changes of PSM and segment size, these spatial measures were not correlated to the timing of segmentation. This shows that the control of time and space of axis segmentation can, in principle, be decoupled. In line with this finding, we identified, using developmental quantitative trait loci (devQTL) mapping, distinct chromosomal regions linked to either the control of segmentation timing or PSM size. We were able to validate the devQTL findings using a CRISPR/Cas9 loss-of-function approach on several candidate genes in vivo. Combined, this study reveals that a developmental constraint mechanism underlies spatial scaling of axis segmentation, while its spatial and temporal control are dissociable modules. Our findings emphasise the need to reveal the selective constraints linking these modules in the natural environment.

developmental biology↗