bioimagesUnknownhttps://www.ebi.ac.uk/biostudies/studies/S-BIAD1193bioimagesSpecimenImage analysisStudy ComponentorganisationBiosampleAssociationsImage acquisitionDiane Pelzer Arghyadip MukherjeeJean-Léon MaîtreMarkus F. SchliffkaJulien G. DumortierfalseInverse blebs operate as hydraulic pumps during mouse blastocyst formationDuring preimplantation development, mouse embryos form a fluid-filled lumen, which sets their first axis of symmetry1,2. Pressurized fluid breaks open cell-cell contacts and accumulates into pockets, which gradually coarsen into a single lumen3–5. During coarsening, cellular adhesive and contractile properties are thought to guide intercellular fluid (IF) but what cell behavior may control fluid movements is unknown. Here, we report large fluid-filled spherical membrane intrusions called inverse blebs6,7 growing into cells at adhesive contacts. At the onset of lumen coarsening, we observed hundreds of inverse blebs throughout the embryo, each dynamically filling with IF and retracting within a minute. We find that inverse blebs grow due to pressure build-up resulting from luminal fluid acc2024-06-14T00:00:00Z2024-07-04T10:39:48.093Z2024-05-30T09:28:50.45ZS-BIAD1193