Acid-soluble nuclear proteins in developmental stages of Lytechinus variegatus

Acid-soluble nuclear proteins extracted from different embryonic stages of the sea urchin Lytechinus variegatus were studied with the use of disc electrophoresis. Comparison of the banding patterns from fertilized eggs, blastulae, and plutei shows that there are qualitative changes in the acid-soluble proteins before blastulation, but that after that time the banding patterns are identical, with the major components showing the same electrophoretic mobility in the stages studied. Since both unfertilized and fertilized eggs show identical banding patterns, while the sperm pattern, apparently lacking in protamines, is entirely different, it would appear that these proteins in the sea urchin are only of maternal origin.