Abstract

We are interested in how shape emerges in the developing embryo focusing in the dynamic functionality associated to Cadherins molecules. In this study we analyze the expression and functionality of two classical Cadherins, E- and N-, along the embryonic-extra-embryonic cell interfase during early morphogenesis in killifish embryo. We reveal that e- and n-cadherin transcripts are maternally provided and proteins express dynamically covering embryonic deep cells layer (DCL) as well as extra-embryonic structures such as epithelial enveloping cell layer (EVL) and yolk syncytial layer (YSL). By using in vivo experimentation we reveal that the extra-embryonic EVL directs cell migration and the spreading of embryonic tissue during early development. This function relies on the ability of DCL cells to couple their autonomous random motility to non-autonomous signals arising from the expansion of the extra-embryonic epithelium, mediated by cell membrane adhesion and cortical tension. E-Cadherin knocking down by using morpholino and/or dominant negative forms (DN-Ecad) of the protein interferes with DCL-EVL cell interaction resulting in the uncoupling of DCL spreading during epiboly. N-Cadherin functionality, in turn, is associated with cell division. Using time-lapse confocal microscopy we noticed that the splitting of genomic DNA during mitosis is compromised in DN-Ncad derived embryos. Multinucleated EVL cells are bigger in size and showed irregular nuclei size distribution. Thus, diverse Cadherins functionality seems to be critical during early morphogenesis in killifish. Furthermore, as E- and N-Cadherin are co-expressed within same cell types understanding the functional crosstalk between both in vivo represent a necessary step to better understand morphogenesis.