Nuclear transfer studies of amoeba proteus after the inhibition of cell division by injection of non-homologous cytoplasm

Following the injection of the post-microsomal supernatant fraction of Amoeba discoides cytoplasm into A.proteus , cell division is inhibited in at least 90% of the recipient cells. Nuclear transfers were performed to determine the site of inhibition in these injected cells. When nuclei from injected, inhibited cells one day after injection were transferred into new A.proteus cytoplasms, 62% of the transfers divided. This ability to promote division declined with the length of time between transfer and the original_ injection. However, when nuclei from A.proteus were transferred into injected, inhibited cytoplasms, only a low number of cells divided, comparable to the number obtained after the injection operation only, namely less than 10%. Thus although many nuclei could recover from inhibition, it was not possible to restore the cytoplasms of inhibited cells by new nuclei.