Transplantation of nuclei from lymphocytes of adult frogs into enucleated eggs: special focus on technical parameters

The technique of transplantation of nuclei from adult lymphocytes into enucleated eggs from Xenopus laevis (South African clawed toad) is described. The splenic lymphocytes from the one-nucleolus mutant were bound via their immunoglobulin receptors to nylon fibers, derivatized with the antigen used for immunization. A technique for coupling other cell types with Woodward reagent is also described. The cells were broken by aspiration into a micropipette and injected into enucleated eggs. The egg pronucleus was eliminated by UV treatment followed by surgical removal. The origin of the genome of developing embryos was determined on karyotype preparations by looking for the nucleolar organizer on the chromosome pair No. 12. Participation of egg pronucleus in development was frequent as judged by the incidence of gynogenetic diploid individuals and of tetraploid animals exhibiting characteristics of both recipient egg and somatic cell donor karyotypes. Apparently normal, lymphocyte-dervived tadpoles were obtained, but they died at 12 days. This shows that differentiated cells from adults, such as lymphocytes, can re-express the genes necessary for ontogeny.