Effects of pronase on the development of reversed symmetry and duplications in the sea urchin, Arbacia punctulata

Abstract

Precleavage zygotes of the sea urchin, Arbacia punctulata, were exposed to Pronase. These treated embryos and nontreated control embryos were reared through metamorphosis. All control larvae developed normal rudiments from the left coelom and associated structures. On the other hand, many of the plutei which had been exposed to Pronase had developed reversed symmetry (i.e., a rudiment on the right side) or a rudiment on both the right and the left sides. The significance of these results with regard to controls of spatial patterning is discussed in terms of gradients of morphogenetic determinants, cell surface properties, adhesiveness, and cell death.