Fig. 1. Grafted postnatal SVZ of the lateral ventricles and embryonic olfactory bulb (OB) generate oligodendrocytes in the corpus callosum. (A-E) Fragments from the SVZ of the lateral ventricles of ß2nZ3'1/1.9 mbp-lacZ bigenic mice were transplanted into the SVZ of wild-type mice, as schematized in A,B (A, donor; B, host). (C) Three weeks later, transplanted mice were analyzed after X-gal staining of frozen coronal sections. The presence of ß-gal-expressing cells in the SVZ of a transplanted animal indicates the site of the graft. (D,E) Mbp⁺ myelinating oligodendrocytes are detectable in the corpus callosum (D), whereas none is seen in the OB (E). In myelinating oligodendrocytes from the donor, the product of X-gal reaction stained the cell body and diffuses along the myelinated fibers. By contrast, ß2nZ3'1⁺ interneurons, which are X-gal positive only in the nucleus, are numerous in the OB (E), illustrating that they have migrated from the graft into the OB. (F-I) Fragments from E17.5 OB from 1.9 mbp-lacZ transgenic embryos were transplanted into the SVZ of the lateral ventricles of P3-P5 wild type, as schematized in F,G (F, donor; G, host). Three weeks later, transplanted mice were analyzed after X-gal staining of frozen coronal sections of the corpus callosum (H) and the OB (I). Mbp⁺ myelinating oligodendrocytes are seen in the corpus callosum but none is detected in the OB.