MOLECULAR MATURATION OF CELL-ADHESION SYSTEMS DURING MOUSE EARLY DEVELOPMENT

During cleavage, the mouse embryo expresses a variety of cell adhesion systems on its cell surfaces. We have reviewed biogenetic and assembl y criteria for the formation of the uvomorulin/catenin, tight junction and desmosome adhesion systems as the trophectoderm differentiates. E ach system reveals different mechanisms regulating molecular maturatio n. Adhesion processes contribute to the generation of distinct tissues in the blastocyst by modifying the expression pattern of blastomeres entering the non-epithelial inner cell mass lineage. Cell adhesion als o influences the spatial organisation, but rarely the timing of expres sion, of proteins involved in trophectoderm differentiation.