The correlation between patterns of dye transfer through gap junctions and future developmental fate in Xenopus : the consequences of u . v . irradiation and lithium treatment

The correlation between cell-to-cell communication through gap junctions at the 32-cell stage and the subsequent patterning of the embryonic axis has been examined in Xenopus laevis embryos. Disturbances of embryonic axis formation were generated by exposure to u.v. irradiation at the vegetal pole before 0-6 in the cell cycle, which generates embryos with dorsal axial deficiencies. Alternatively embryos were treated with 100 mM-lithium chloride between the 2-celI and 32-cell stage, which generates embryos with ventral axial deficiencies. The cell-to-cell transfer of Lucifer Yellow was used to monitor junctional permeability. Injections were made into animal hemisphere cells, lying in tiers 1 and 2 of the 32-cell embryo, whose position relative to the future dorsoventral axis of the embryo was determined on the basis of differences in pigmentation. The frequency of Lucifer Yellow transfer in the future dorsal half of the animal hemisphere was compared with that in the future ventral half for control (untreated), u.v.irradiated and Li-treated embryos. Injected embryos were subsequently scored for axial development for comparison with dye transfer frequencies.