Functional identification of three components which mediate tissue-type specific embryonic cell adhesion

Abstract

VARIOUS hypotheses have been suggested to explain in vitro reconstruction of tissues from populations of dispersed embryonic cells^1–5, all asserting that it is based on selective adhesion. Although selective adhesion has been amply demonstrated^6–8, its molecular basis as well as the identity and number of components involved remains to be defined. Supernatant solutions from cell and tissue cultures have been reported to yield a component(s) apparently involved in the enhancement of cell aggregation^9–11. In addition a component(s) in the supernatant binds at the cell surface and is specific to the cell type from which the supernatant is prepared¹¹. These results suggested the existence of specific receptors at the cell surface that are complementary to the aggregation promoting molecules (APM). We have now found that the binding factor participates directly in adhesion and that another component must be present for adhesion to be complete.