Apoptosis in sea urchin embryos.

It is demonstrated by DNA electrophoresis analysis, morphological observations and TdT in situ reaction, that Paracentrotus embryos if treated with TPA plus heat undergo an apoptotic reaction. Indication is also obtained that non treated embryos undergo spontaneous apoptosis at the early pluteus stage, especially in the districts of arms and intestine. The possible meaning of this latter observation is discussed.