The enhancement of reaggregation of sea urchin blastula cells by exogenous proteins

The ability of exogenous proteins to enhance the reaggregation of aggregation-deficient butanol extracted cells has been studied using blastula cells of the sea urchin Arbacia punctulata. Butanol extracts, calcium- and magnesium-free sea-water dissociation supernatant, human plasma fibronectin and bovine serum albumin enhance reaagregation in a concentration dependent manner. Electrophoretic analysis and autoradiography of 125I surface labeled dissociated cells indicate that while butanol extracts a large number of proteins, few iodinated proteins are present in the butanol extract. The non-specificity of proteins to promote reaggregation and the probable cellular location of the butanol extracted proteins are discussed.