[P2.30]: Low tryptophan diet disturbs neuronal migration during ontogeny

diverge to give birth to two subtypes of interneurons, INV2a (Chx10+) and INV2b (Gata3+). Several transcription factors such as Nkx6.1, Irx3, FoxN4, Gata2 and Mash1, have been involved during InV2 development. In addition, although the TGFb/Activin pathway has been shown to induce the emergence of V2a, the question of its influence on Dll4-dependent notch activation, which promotes the V2b fate, has not been raised. Obviously the arising of INV2a/INV2b relies on a highly complex molecular network, whose main participants appear to be identified, whereas the precise role of each of them is far from being fully understood, especially with regard to Gata2. In order to gain more complete insight into this molecular network, we have further analyzed genetic interactions by gainand loss-of-function studies. Our results are consistent with a participation of Gata2 first in the generation of precursors common to INV2a and INV2b in the p2 domain, secondly in the promotion of the INV2b genetic program at the expense of that of INV2a. Both functional aspects involve regulatory loops between Gata2 and Nkx6.1, FoxN4, Dll4, Mash1 and, in addition, the interference of Gata2 with the TGFb/Activin pathway. Our studies have thus allowed to gain further insight into the role played by Gata2 during the emergence of INV2 and to further understand molecular events involved in this complex neuronal differentiation process.