Pattern of protein synthesis in dissociated embryonic cells of Xenopus laevis whose reaggregation was inhibited by Ca ²⁺ -deprivation and by mechanical interference

Protein synthesis was studied in dissociated Xenopus embryonic cells whose reaggregation was inhibited either chemically (deprivation of Ca ²⁺ ) or mechanically (cultivation on sintered glass filter). Under reaggregation-inhibited conditions, synthesis of several proteins was inhibited in neurula but not in blastula and gastrula cells. Under reaggregating conditions, pattern of protein synthesis in blastula cells became 'neurula-cell-type' after 17 h. However, under non-reaggregating conditions, activation of many proteins was inhibited. The inhibition was mostly reversible and similar to that observed in neurula cells inhibited by actinomycin D. Thus, synthesis of many proteins directed by new transcripts at the neurula stage appears to depend on the maintenance of cell-to-cell contact.