Printed in Great Britain © Company of Biologists Limited 1977 Nuclear transplantation from intestinal epithelial cells of early and late Xenopus laevis tadpoles

The aim of these experiments was to test whether the developmental potential of nuclei from intestinal epithelial cells of Xenopus laevis tadpoles declined during the life of the functional larval gut. The results of transplantation of nuclei from three different stages of development were compared: stages 46-48, when feeding begins and while yolk is still present but before the formation of the typhlosole; stage 57, just prior to the onset of meta-morphic reorganization; and stage 54, an intermediate stage. The results showed that there was no change in developmental potential of these nuclei during the life of the larval gut, thereby disproving the hypothesis that nuclear transplants from intestinal epithelial cells of early tadpoles of X. laevis will support extensive development because the cells are not fully functional. However, nuclei from the intestinal epithelial cells were less able to support development than blastula nuclei. It was concluded therefore, that the developmental potential of the gut nuclei is restricted relative to that of the blastula nuclei, but that these restrictions are reversed in a small proportion of cases