Godeau, Amélie L.Marin-Riera, MiquelTrubuil, EliseRogalla, SvanaBengoetxea, GuillermoBacková, LenkaPujol, ThomasColombelli, JulienSharpe, JamesMartin-Blanco, EnriqueSolon, Jérôme2025-09-052025-09-052025Godeau AL, Marin-Riera M, Trubuil E, Rogalla S, Bengoetxea G, Backová L, et al. A transient contractile seam promotes epithelial sealing and sequential assembly of body segments. Nat Commun. 2025 Apr 29;16(1):4010. DOI: 10.1038/s41467-025-58566-z2041-1723http://hdl.handle.net/10230/71116In embryos, epithelial sealing proceeds with progressive zipping eventually leading to a scar-free epithelium and ensuring the assembly of body segments in insects and neural tube in mammals. How zipping is mechanically controlled to promote tissue fusion on long distances, remains unclear. Combining physical modeling with genetic and mechanical perturbations, we reveal the existence of a transient contractile seam that generates forces to reduce the zipping angle by force balance, consequently promoting epidermal sealing during Drosophila embryogenesis. The seam is formed by the adhesion of two tissues, the epidermis and amnioserosa, and is stabilized by the tensions generated by the segment boundaries. Once a segment is zipped, the seam disassembles concurrently with the inactivation of the Jun kinase pathway. Thus, we show that epithelial sealing is promoted by a transient actomyosin contractile seam allowing sequential segment assembly.application/pdfeng© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.info:eu-repo/semantics/articlehttp://dx.doi.org/10.1038/s41467-025-58566-zCytoskeletonMorphogenesisMulticellular systemsinfo:eu-repo/semantics/openAccess