Cell-cell Interactions In Development Research Articles

Cell-Cell Interactions in Development

Cell-Cell Interactions in Development

Session 11: Cell-cell interactions in development

Session 11: Cell-cell interactions in development

Differential recognition by proteins of alpha-galactosyl residues on endothelial cell surfaces.

The binding of proteins to cell surface carbohydrates contributes to cell-cell interactions in development, immunity, and various physiologic processes. Such interactions are presumably dictated not only by the chemical structure of the carbohydrate but also reflect the properties of the protein and the microenvironment in which the protein-carbohydrate interaction occurs. To explore the factors influencing the recognition of cell surface carbohydrates by proteins, the extent to which three classes of proteins--anti-Gal alpha 1-3Gal IgM found in higher primates, Griffonia simplicifolia type I lectin, isolectin B4 (GS-IB4), and alpha-galactosidase--interact with Gal alpha 1-3Gal on porcine cell surfaces was tested. Although the Gal alpha 1-3Gal residues expressed on porcine endothelial cells and recognized by anti-Gal alpha 1-3Gal IgM and GS-IB4 were both sensitive to cleavage by alpha-galactosidase, the sites recognized by GS-IB4 were more sensitive to cleavage than sites recognized by anti-Gal alpha 1-3Gal IgM. Cross-blocking studies on porcine cell surfaces revealed that a significant proportion of anti-Gal alpha 1-3Gal IgM bound to sites not recognized by GS-IB4; however, anti-Gal alpha 1-3Gal IgM and GS-IB4 recognized the same sites on solubilized membrane proteins and model compounds. These results suggest that features of the cell surface such as the three-dimensional arrangement of Gal alpha 1-3Gal and characteristics of the protein such as size and valency play critical roles in specific interactions on cell surfaces.

The role of cell-cell interactions in postembryonic development of the Caenorhabditis elegans germ line

This review addresses the role of cell-cell interactions in the development of the Caenorhabditis elegans germ line: specifically, the relative contributions of germ-line-soma interactions versus autonomous processes are considered. Current knowledge of the interacting cell types and the genes essential for various aspects of germ-line development is discussed.

A new marker for identifying quail cells in embryonic avian chimeras: a quail-specific antiserum.

The characterization of cell behavior in quail chick chimeras has greatly increased our knowledge of the ontogeny of embryonic cell populations and the role of cell-cell interactions in development. We sought to extend the value of avian chimeras by producing a marker that would recognize cell surface components and that could be used instead of the traditional nuclear marker to identify quail cells within chimeras. We describe here a quail-specific antiserum produced by injecting chickens with a membrane fraction of 6-10-day quail embryos. By use of peroxidase coupling of a second antibody, serum reactivity was tested in tissue sections of normal quail and chick embryos and of somitic mesoderm and neural tube chimeras. The primary time period examined was 6-10 days of development. At these stages, the antiserum recognizes only quail cells and stains both plasma membrane-associated and cytoplasmic cell components. The latter characteristics allow the identification of quail axons in chimeras and facilitate visualization of quail cells at low magnification. We show that antiserum staining can also be used to identify quail cells in culture and can be combined with orthograde HRP labeling of neurons.

Teratogenic drugs inhibit tumour cell attachment to lectin-coated surfaces.

Interactions between embryonic cells are generally thought to have a central role in the control of development. When these morphogenic interactions are interrupted by either physical intervention or genetic defects, normal development is impaired. In accord with these experiments, specific interactions between embryonic cells have been demonstrated in several in vitro systems. Many investigators have described homotypic aggregation of chick embryo cells, and heterotypic specificity has been described. Because of the importance of morphogenic cell-cell interactions in development it follows that agents that interfere with these interactions, regardless of the interference mechanism, are potential teratogens. Here we have used a simple in vitro cell to surface recognition system in an attempt to screen for potential teratogens. We have found a very high correlation between inhibitory activity in the in vitro assay and reported teratogenic activity in human or animal studies. This suggests that many teratogenic agents may act by interfering, in an as yet unknown way, in normal cell to cell interactions.