Gap junctions in development.

Almost since their discovery gap junctions have attracted attention as possible means by which cell growth and cell development could be controlled since they provide for direct cell-cell communication (Potter et al, 1966; Loewenstein, 1968; Sheridan, 1968; Crick, 1970; Bennett, 1973). A corollary, of course, is that gap junctions play an important role in embryogenesis. This idea is made especially appealing by the fact that the junctions appear early (Slack and Palmer, 1969; Tupper and Saunders, 1972; Bellairs et al., 1975; Ducibella et al, 1975; Lo and Gilula, 1979; Hanna et al., 1980; Turin and Warner, 1980; Goodall and Johnson, 1982; McLachlin et al., 1983) and that there is often a close temporal correlation between changes in the junctional complement and important embryological events (Revel et al., 1973; Warner, 1973; Tickled al., 1975; Kelley and Fallon, 1978; Lo and Gilula, 1979; Pitts, 1980). My presentation summarizes the changes that take place injunctions at various stages and critically evaluates the significance of these changes in terms of development.