TELENCEPHALIC TRANSPLANTS IN MICE - CHARACTERIZATION OF GROWTH AND DIFFERENTIATION PATTERNS

Telencephalic grafting represents a powerful tool for developmental st udies and for the investigation of biological features of transgenic b rain tissue. The interpretation of grafting experiments, however, requ ires detailed knowledge of graft biology, Therefore, we have character ized growth rates, graft size, and differentiation of embryonic telenc ephalic tissue harvested at various developmental stages and grafted i nto the caudoputamen and lateral ventricles of histocompatible mice, A total of 164 grafts were analysed up to 500 days after transplantatio n. Of all transplants, 79.3% resulted in the formation of solid neural grafts. Grafted cells were identified by H-3-thymidine labelling and autoradiography, Proliferation was studied by bromodeoxyuridine incorp oration and decreased from an initial 35% at 1-3 d after grafting to l ess than 1,6% after 40 days, The graft size was measured as a function of the embryonic age of the transplanted tissue, Our data indicate th at telencephalic tissue harvested at embryonic day E 12.5 reproducibly yields large, fully differentiated neuroectodermal grafts. The parame ters defined in this study will be useful for detailed analysis of neu roectodermal tissue from mice undergoing fatal neurodegeneration, such as knockout mice bearing lethal mutations.