Fig. 4. Low levels of Shh are detected in the rostral telencephalon. (A) Sagittal cryosection of E10.5 mouse forebrain hybridized with Shh digoxigenin-labeled antisense cRNA probe. The most rostral signal for Shh is in the anterior entopeduncular area (AEP), caudal to the medial ganglionic eminence (MGE). No hybridization signal for Shh is detected in the rostral (RT) and dorsal (DT) telencephalon. AHy, anterior hypothalamus; ChPl, choroid plexus; OR, optic recess. (B) mRNA was extracted from rostral (RT), caudal (CT) and dorsal (DT) explants derived from E9.5 and E10.5 telencephalon at the time of isolation (lane 0) or after 5 (lane 5) and 10 (lane 10) days in vitro and subjected to RT-PCR with primers specific for Shh. In contrast to data obtained by in situ hybridization, a definite positive signal for Shh is amplified from E9.5- and E10.5-derived rostral territory explants at the time of isolation. In dorsal explants, Shh is detected only after 10 or 5 days in vitro for E9.5- or E10.5-derived explants, respectively. Scale bar: 220 µm.
