Nuclear Control of Enzyme Synthesis in Acetabularia

Abstract

1. The influence of enucleation on the synthesis of two enzymes, invertase and acid phosphatase, was studied in Acetabularia mediterranea. Whole and rhizoid-amputated algae 15-17 mm. and 30 mm. long were investigated as well as certain defined fragments 12 mm. long. 2. Acid phosphatase synthesis was dependent to a great extent on the presence of the nucleus. The synthesis of this enzyme ceased shortly after enucleation in rhizoid-amputated plants. Non-nucleated fragments of Acetabularia did not show any increase in acid phosphatase activity after dissection. 3. Only a remote control of the cell nucleus on invertase synthesis was indicated from the data obtained. Rhizoid-amputated algae and tip fragments formed considerable amounts of invertase after enucleation. 4. The existence of a hypothetical substance of nuclear origin is postulated which seems to be consumed in the cytoplasm during enzyme formation. 5. No correlation between synthesis of enzymes and synthesis of total protein could be found in enucleated systems.