Fig. 7.
Labeling of tangential migrations from the ganglionic eminences to the marginal zone (MZ). Embryonic day 14 (E14) slices were injected with CellTracker green (CMFDA) or CellTracker orange (CMTMR) in the ganglionic eminences and cultured for 2 days. After CMTMR injection in the lateral ganglionic eminence (LGE), labeled cells had migrated towards the most ventral part of the forebrain (15 out of 15 slices) and dorsally to the neocortex (not shown). (A─C) Dye injections into both the medial ganglionic eminence (MGE)- and LGE-labeled cells that ended their migration into the neocortex. Shown is the absence of CMTMR and CMFDA costaining after 2 days in vitro (D.I.V.). (C) Labeled cells in the LGE and the MGE may easily be distinguished from each other. More importantly, MGE-generated neurons could be labeled when they pass through the LGE. (D─F) Time-delayed injections (LGE injected with CMTMR 4 hr after a CMFDA injection in the MGE; n = 4) resulted in virtually complete costaining of cells that have migrated to the neocortex, indicating that the MGE is the main source of subpallial neurons migrating tangentially to the neocortex at E14. Gray arrow in F points to a cell labeled only with CMTMR. (G) Two days in vitro after a CMFDA injection, a densely packed group of labeled cells was found in the MZ. (H) Similar cells were not reelin-immunoreactive. (Scale bars: A─C, 30 ?m; D─F, 25 ?m; G, 50 ?m; and H, 20 ?m.)