A new extracellular matrix protein in sea urchin eggs

A new extracellular matrix protein has been purified from eggs of the Mediterranean sea urchin, Paracentrotus lividus . The molecule is a 210 kD dimer consisting of two 105 kD subunits that are held together by S-S bridges. In the unfertilized eggs, the protein is found within granules uniformly distributed throughout the cytoplasm. A similar protein has been also obtained from gonads of the Japanese sea urchin, Temnopleurus hardwickii . These proteins may correspond to the collagen-binding proteins synthesized during the early stages of development in the embryos of Hemicentrotus pulcherrimus, Anthocidaris crassispina, Pseudocentrotus depressus and Dendraster excentricus .