Proliferation and patterning in the embryonic chick hypothalamic ventral midline

Previous studies in the lab have shown that anterior-most floor plate cells undergo a change in fate in response to BMP-Tbx2 mediated signalling and give rise to ventral midline hypothalamic cells. In this study I have further characterised the ventral midline of the hypothalamus in the E4-E7 chick embryo. I demonstrate that the hypothalamic ventral midline is a complex structure comprised of distinct regions along its anterior-posterior axis. Fate-mapping studies demonstrate unequivocally that presumptive hypothalamic floor plate cells give rise to recognisable parts of the hypothalamus, In particular to the retrochiasmic, tubero-infundibular and mammillary regions and to distinct morphological structures, including the infundibulum and mammillary pouch.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Foxp1 Regulates Neural Stem Cell Self-Renewal and Bias Toward Deep Layer Cortical Fates

The laminar architecture of the mammalian neocortex depends on the orderly generation of distinct neuronal subtypes by apical radial glia (aRG) during embryogenesis. Here, we identify critical roles for the autism risk gene Foxp1 in maintaining aRG identity and gating the temporal competency for deep-layer neurogenesis. Early in development, aRG express high levels of Foxp1 mRNA and protein, which promote self-renewing cell divisions and deep-layer neuron production. Foxp1 levels subsequently decline during the transition to superficial-layer neurogenesis. Sustained Foxp1 expression impedes this transition, preserving a population of cells with aRG identity throughout development and extending the early neurogenic period into postnatal life. FOXP1 expression is further associated with the initial formation and expansion of basal RG (bRG) during human corticogenesis and can promote the formation of cells exhibiting characteristics of bRG when misexpressed in the mouse cortex. Together, these findings reveal broad functions for Foxp1 in cortical neurogenesis