Gap junctional units are functionally expressed before first cleavage in the early ascidian embryo.

摘要: Manually apposed ascidian zygotes established electrical communication within 50 min of fertilization and before cytokinesis. Junctional conductance between was 14.5 +/- 2.9 nS (n = 7), similar to that previously reported for two-cell-stage blastomeres, suggesting blastomeres express an equivalent number gap junctional half-channels. Because puromycin at 400 microM does not inhibit the functional expression these half-channels, they appear be maternal origin their activation require protein synthesis. Loading with 500 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid or exposing 10 calcium ionophore A-23187 shows half-channels are regulated by intracellular calcium, consistent behavior channels in adult tissues. The results show units expressed zygote stage.