Cell surface antigens in early mammalian development

Cell surface molecules are known to be functionally important In a number of developmental systems. Molecular components of the cell surface may participate in Intercellular adhesion, recognition and communication. Reactions occur r Ing at the cell surface may also influence developmental events by Induci ng i ntracelIular changes In cellular metabolism and gene expression which may, In turn, alter the composition and/or organization of surface components. Sequences of reactions mediated by cell surface molecules are probably Important In directing undifferentiated embryonic cells along specific dlfferentlatlve pathways.In the early development of the mammal Ian embryo, important events occurring during the preimplantation period are likely to require the participation of specific cell surface molecules. For example, these are likely to Include sperm-egg attachment and fusion, Interbl astomere adhesion, blastulatlon, and attachment of the blastocyst to the uterine epithelium. During preimplantation mouse development, specific stage-relaged changes in the qual itatlve and quantitative nature of the proteins synthesized and those expressed on the cell surface have been documented.