TY - JOUR
T1 - Fgf8 and Gbx2 induction concomitant with Otx2 regression is correlated with midbrain-hindbrain fate of caudal prosencephalon
AU - Hidalgo-Sánchez, Matías
AU - Simeone, Antonio
AU - Alvarado-Mallart, Rosa Magda
PY - 1999/7
Y1 - 1999/7
N2 - Chick/quail transplantation experiments were performed to analyse possible factors involved in the regionalisation of the midbrain-hindbrain domain. The caudaI prosomeres, expressing Otx-2, were transplanted at stage HH10 into rostrocaudal levels of the midbrain-hindbrain domain, either straddling the intra-metencephalic constriction (type 1 grafts), or at rostral and medial levels of pro-rhombomere A1 (type 2 and 3 grafts, respectively); thus, in all situations, one border of the graft was in contact with the host Gbx2- and Fgf8-expressing domains. The area containing the graft, recognised by QCPN immunohistochemistry was first analysed 48 hours after transplantation for Otx2 Gbx2, En2 and Fgf8. Although in all three situations, a large part of the graft maintained Otx2 expression, another part became Otx2 negative and was induced to express Gbx2 and Fgf8. These inductive events occurred exclusively at the interface between the Otx2-positive transplanted domain and the ipsilateral host Gbx2-positive rhombomere 1, creating a new Otx2-Gbx2 boundary within the grafted territory. In type 1 and 2 grafts, the induced Fgf8 domain is in continuity with the host Fgf8 isthmic domain, whereas for type 3 grafts, these two domains are separate. High levels of En2 expression were also induced in the area expressing Gbx2 and Fgf8, and Wnt1 and Pax2 expressions, analysed in type 3 grafts, were induced at the intragraft Otx2-Gbx2 new boundary. Moreover, at later embryonic stages, the graft developed meso-isthmo-cerebellar structures. Thus, gene expressions induced in the grafted prosencephalon not only mimicked the pattern observed in the normal midbrain-hindbrain domain, but is followed by mid brain-hindbrain cytodifferentiation, indicating that not only Fgf8 but also confrontation of Otx2 and Gbx2 may play an essential role during midbrian-hindbrain regionalisation.
AB - Chick/quail transplantation experiments were performed to analyse possible factors involved in the regionalisation of the midbrain-hindbrain domain. The caudaI prosomeres, expressing Otx-2, were transplanted at stage HH10 into rostrocaudal levels of the midbrain-hindbrain domain, either straddling the intra-metencephalic constriction (type 1 grafts), or at rostral and medial levels of pro-rhombomere A1 (type 2 and 3 grafts, respectively); thus, in all situations, one border of the graft was in contact with the host Gbx2- and Fgf8-expressing domains. The area containing the graft, recognised by QCPN immunohistochemistry was first analysed 48 hours after transplantation for Otx2 Gbx2, En2 and Fgf8. Although in all three situations, a large part of the graft maintained Otx2 expression, another part became Otx2 negative and was induced to express Gbx2 and Fgf8. These inductive events occurred exclusively at the interface between the Otx2-positive transplanted domain and the ipsilateral host Gbx2-positive rhombomere 1, creating a new Otx2-Gbx2 boundary within the grafted territory. In type 1 and 2 grafts, the induced Fgf8 domain is in continuity with the host Fgf8 isthmic domain, whereas for type 3 grafts, these two domains are separate. High levels of En2 expression were also induced in the area expressing Gbx2 and Fgf8, and Wnt1 and Pax2 expressions, analysed in type 3 grafts, were induced at the intragraft Otx2-Gbx2 new boundary. Moreover, at later embryonic stages, the graft developed meso-isthmo-cerebellar structures. Thus, gene expressions induced in the grafted prosencephalon not only mimicked the pattern observed in the normal midbrain-hindbrain domain, but is followed by mid brain-hindbrain cytodifferentiation, indicating that not only Fgf8 but also confrontation of Otx2 and Gbx2 may play an essential role during midbrian-hindbrain regionalisation.
KW - Cerebellum
KW - Chick/quail chimera
KW - En2
KW - Isthmic organiser centre
KW - Mesencephalon
KW - Neural tube
KW - Pax2
KW - Segmentation
KW - Wnt1
UR - http://www.scopus.com/inward/record.url?scp=17744421146&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=17744421146&partnerID=8YFLogxK
M3 - Article
C2 - 10375509
AN - SCOPUS:17744421146
VL - 126
SP - 3191
EP - 3203
JO - Development (Cambridge)
JF - Development (Cambridge)
SN - 0950-1991
IS - 14
ER -