John Gurdon
De Robertis carried out his postdoctoral training (1974–1977) with Sir John Gurdon, the distinguished developmental biologist, at the Medical Research Council in the United Kingdom. By transplanting Xenopus kidney cell nuclei into oocytes of a different amphibian species, they demonstrated that nuclear reprogramming of protein-coding genes was caused by oocyte cytoplasm. In 1978 he became staff scientist at the MRC Laboratory of Molecular Biology in Cambridge, working on the nucleo-cytoplasmic transport of macromolecules.