Acid-soluble phosphate metabolism in nuclei from rat thymus gland

The discovery of nuclear phosphorylation and of the ability of isolated nuclei to incorporate protein and nucleic acid precursors (Allfrey, Mirsky & Osawa, 1955, 1957 a) focused attention on the part that might be played by the nucleus in the metabol- ism of the whole cell. On the other hand, thymus nuclei isolated in an aqueous medium re- tained nucleotides (Allfrey et al. 1955) so that some process might be envisaged by which precursor molecules are held in the nucleus before the for- mation there of new molecules. We therefore attempted to define more precisely the relationship between acid-soluble phosphate metabolism in the nucleus and that in the whole cell and this led to some observations on uptake of inorganic phosphate and arginine by nuclei from rat-thymus glands which may be relevant in other types of animal cells.