Three cell recognition changes accompany the ingression of sea urchin primary mesenchyme cells

摘要: At gastrulation the primary mesenchyme cells of sea urchin embryos lose contact with extracellular hyaline layer and neighboring blastomeres as they pass through basal lamina enter blastocoel. This delamination process was examined using a cell-binding assay to follow changes in affinities between their three substrates: hyalin, early gastrula cells, lamina. Sixteen-cell-stage micromeres (the precursors cells), obtained from mesenchyme-blastula-stage were used conjunction raised culture intermediate ages. The exhibited an affinity for but lost at time ingression vivo. Similarly, had monolayers older much cell-to-cell affinity. Presumptive ectoderm endoderm tested against showed no decrease binding over same interval. When preparations, there increase that associated developmental time. change Binding measurements isolated laminar components identified fibronectin one molecule which wandering acquired specific data indicate presumptive leave vegetal plate embryo hyalin gain matrix lines