ABSTRACT
Many in vivo and in vitro studies suggest that the extracellular matrix has a crucial role in the development of an embryo. Recently we have purified a new extracellular matrix protein from eggs of the sea urchin Paracentrotus lividus. The molecule consists of two 105 kDa subunits and serves as adhesion substrate for embryonic cells. We named the protein Pl-nectin because of its function and the species from which it has been purified. Here we describe the antigen localization at different developmental stages starting from the unfertilized egg to the pluteus larva. Furthermore we attempted a comparative biochemical analysis between Pl-nectin and other two similar American and Japaneese extracellular matrix proteins. We have evidence that Pl-nectin is a new molecular species and propose that it is essential in guiding the morphogenetic cell movements occurring at gastrulation.
