Fucosylated glycoconjugates appear on mouse embryos during blastocyst formation

Mouse embryos were analysed for expression of surface glycoconjugates using a panel of fluorescein‐labelled lectins. Morulae and blastocysts but not early cleavage stages stained brightly with fucose binding lectins. By contrast, cleavage stages stained brightly with all the other lectins tested. These findings provide evidence for substantial reorganisation of the cell surface during blastocyst formation and are consistent with a role for fucosylated glycoconjugates in compaction.