Identification of distinct telencephalic progenitor pools for neuronal diversity in the amygdala

Abstract

Development of the amygdala, a central structure of the limbic system, remains poorly understood. Using mouse as a model, our studies reveal that two spatially distinct and early specified telencephalic progenitor pools marked by the homeodomain transcription factor Dbx1 are major sources of neuronal cell diversity in the mature amygdala. We find that Dbx1+ cells of the ventral pallium (VP) generate excitatory neurons of the basolateral complex and cortical amygdala nuclei. Moreover, Dbx1-derived cells comprise a novel migratory stream that emanates from the preoptic area (POA), a ventral telencephalic domain adjacent to the diencephalic border. The Dbx1+ POA-derived population migrates specifically to the amygdala, and as defined by both immunochemical and electrophysiological criteria, generates a unique subclass of inhibitory neurons in the medial amygdala nucleus. Thus, this POA-derived population represents a novel progenitor pool dedicated to the limbic system.

The COUP-TFII/Neuropilin-2 is a molecular switch steering diencephalon-derived GABAergic neurons in the developing mouse brain

“…Hirata et al analyzed birthdates of migrating neurons from the POa to the amygdala and found that POa-derived cells labeled by tamoxifen injection from E9.5 to E11.5 populated the medial amygdala in Dbx-1 CreER T2 mice with a peak at E10.5 and E11.5 (10). Our data showed that electroporation at E12.5 to the POa also gave rise to the CMS from the POa (Fig.…”

“…Using Dbx1-Cre mice, Hirata et al demonstrate that amygdala GABAergic neurons derived from the POa form a migratory stream called the POa amygdala migratory stream (10). The results presented here demonstrate the presence of a POa-derived CMS that supplies GABAergic neurons to the caudal telencephalon, including at least the medial amygdala and neocortex.…”

“…The migration of the POa-derived cells is poorly understood, although recently this population has been revealed to be the source of GABAergic In utero electroporation, E11.5 to E13.5 neurons in the neocortex and the amygdala (8)(9)(10). The present findings show that the POa-derived cells that were migrating to the neocortex and the amygdala initially shared the migratory stream and then took separate paths controlled by the dynamic expression of COUP-TFII and Nrp2.…”

“…Recent studies using Nkx5.1-Cre and Dbx1-Cre mice show the preoptic area (POa) as a new source of cortical GABAergic neurons containing an Lhx6-expressing population (8,9). Other investigators report that the POa supplies GABAergic neurons to the medial nucleus of amygdala, in a study using Dbx1-Cre knock-in mice (10). The neurons migrate caudally to the amygdala via the ventral GE.…”

A Novel Transient Glutamatergic Population Migrating from the Pallial–Subpallial Boundary Contributes to Neocortical Development

“…Glutamatergic Dbx1-derived CP neurons are generated by progenitors at the PSB The Dbx1 gene was shown to be specifically expressed in the ventricular zone of the ventral pallium (VP) at the PSB with a caudal high rostral low gradient, in the septum and in the preoptic area (POA)/anterior entopenduncular area (AEP) (Yun et al, 2001;Medina et al, 2004;Bielle et al, 2005;Hirata et al, 2009). We previously reported that Dbx1-expressing progenitors at the PSB generate Reln ϩ CajalRetzius neurons between E10.5 and E11.5 (Bielle et al, 2005).…”