NUCLEI CAN BE ISOLATED FROM THE EGGS AND EMBRYOS OF THE SEA URCHIN BY A FOUR STEP METHOD: (1) washing with dextrose solution until the cells become weak, (2) cytolysis in 0.002 M Mg(++) solution, (3) homogenization of the cytolyzed cells by agitation, and (4) separation of the nuclei from the rest of the homogenate by centrifugation on a layered sucrose gradient. Contamination of the isolated nuclei is less than 1 per cent. The yield varies between 20 per cent and 80 per cent depending on the developmental stage used.
NUCLEI CAN BE ISOLATED FROM THE EGGS AND EMBRYOS OF THE SEA URCHIN BY A FOUR STEP METHOD: (1) washing with dextrose solution until the cells become weak, (2) cytolysis in 0.002 M Mg(++) solution, (3) homogenization of the cytolyzed cells by agitation, and (4) separation of the nuclei from the rest of the homogenate by centrifugation on a layered sucrose gradient. Contamination of the isolated nuclei is less than 1 per cent. The yield varies between 20 per cent and 80 per cent depending on the developmental stage used.