[Abstract Title]. - Society for Neuroscience

addition, the pyramidal tract marked by reporter EGFP was largely diminished. Consistent with
this, the expression of Ctip2, which is a gene required for the specification of the deep layer
cortico-spinal tract neurons was absent in Emx1Cre/+ FoxG1c/c animals at E18.5. Surprisingly,
these mutants live at least until the age of 3 weeks with a very thin layer of cortex with almost
80% reduction. To better understand the role of FoxG1 in cortical plate formation, we removed
this gene from the pyramidal neuron progenitors in a mosaic manner at a time coincident with
them becoming postmitotic. The FoxG1 null cells failed to penetrate into the cortical plate and
remained underneath the subplate, despite having initiated the expression of Ctip2. We also
observed migration defects in ventral telencephalic neurons upon removal of FoxG1. This raises
the possibility that FoxG1 is universally required for the telencephalic progenitors to migrate out
from their respective progenitor domains.
Disclosures: G. Miyoshi , None; V. Sousa, None; C. Hanashima, None; G. Fishell, None.
Poster
230. Cell Migration: Molecules Mediating Migration
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 230.23/B13
Topic: A.02.c. Cell migration
Support: BBSRC
Title: Role of vascular endothelial growth factor and blood vessels in the development of GnRH
neurons
Authors: *A. CARIBONI 1,2 , C. RUHRBERG 1 , S. RAKIC 1 , K. DAVIDSON 1 , E. DOZIO 2 , R.
MAGGI 2 , J. G. PARNAVELAS 1 ;
1 Univ. Coll London, London, United Kingdom; 2 Univ. of Milan, Milan, Italy
Abstract: Gonadotropin-releasing hormone (GnRH) neurons, a small number of cells scattered
in the hypothalamus, play an essential role in reproductive function. During development, these
neurons originate in the olfactory placode and migrate along olfactory/vomeronasal axons in the
nasal compartment to gain access into the forebrain and reach their final positions in the
hypothalamus. In humans, failure of GnRH neurons to migrate normally results in delayed or
absent pubertal maturation and infertility. The movement of these cells through changing
molecular environments suggests that numerous factors are involved in their migration. We have
recently described that classical neuronal guidance molecules, such neuropilins (NRPs), are
expressed by GnRH neurons, and established the importance of NRP2 in their migration in vivo.
Using immortalised GnRH cells (GN11), we also found that two NRP ligands modulate their