Changes in deoxyribonucleoside triphosphate pools in the starfish oocyte during maturation and early embryogenesis

dNTP pools are quite low in immature oocytes of the starfish, expand during the 1-methyladenine-induced maturational process and thereafter reach a maximal level (approx. 35, 20, 15 and 5 fmoles/egg for dTTP, dCTP, dATP and dGTP, respectively) which is maintained in overmatured eggs. Maturing oocytes were inseminated at the stage just before extrusion of the first polar body and determination of dNTP pools during early embryogenesis showed the same expansion pattern as that of the 1-methyladenine-treated oocytes. Therefore, the increase in dNTP pools during early embryogenesis is dependent on 1-methyladenine (1-MA) but independent of fertilization. Aphidicolin, a specific inhibitor of eukaryotic DNA polymerase alpha, has no effect on dNTP pool size in 1-methyladenine-treated oocytes, but causes considerable expansion of dNTP pools in fertilized eggs which cleave achromosomally in the presence of the drug.