Genetic regulation of arealization of the neocortex

Abstract

Arealization of the neocortex is controlled by a regulatory hierarchy beginning with morphogens secreted from patterning centers positioned at the perimeter of the dorsal telencephalon. These morphogens act in part to establish within cortical progenitors the differential expression of transcription factors that specify their area identity, which is inherited by their neuronal progeny, providing the genetic framework for area patterning. The two patterning centers most directly implicated in arealization are the commissural plate, which expresses fibroblast growth factors, and the cortical hem, which expresses bone morphogenetic proteins and vertebrate orthologs of Drosophila wingless, the Wnts. A third, albeit putative, patterning center is the antihem, identified by its expression of multiple signaling molecules. We describe recent findings on roles for these patterning centers in arealization. We also present the most recent evidence on functions of the four transcription factors, Emx2, COUP-TFI, Pax6, and Sp8, thus far implicated in arealization. We also describe screens for candidate target genes of these transcription factors, or other genes potentially involved in arealization. We conclude with an assessment of a forward genetics approach for identifying genes involved in determining area size based in part on quantitative trait locus mapping, and the implications for significant differences between individuals in area size on behavioral performance.

Genome-wide association study of bipolar I disorder in the Han Chinese population

“…27 It is a crucial developmental event as the neocortical areas form the basis for sensory perception, control of movements and mediate our behavior. 28 The gene ST8SIA2 (previously known as SIAT8B) located close to rs8040009 on a hypothetical protein C15orf32, whose role in the pathogenesis of bipolar I disorder is not clear. However, ST8SIA2 has been found to associate with both schizophrenia and bipolar disorder in one recent study using genomewide microsatellite scan, 29 implying that ST8SIA2 may lie in a common pathway for the development of bipolar and schizophrenia.…”

Emx2 and Foxg1 Inhibit Gliogenesis and Promote Neuronogenesis

“…Each subroutine is controlled by dedicated molecular machineries [22][23][24]. Developmentally regulated, secreted factors and transcription factors (TFs) managing spatiotemporal information further act as hubs, harmonically coordinating all these subroutines [22,[25][26][27]. Among these TFs there are Emx2 and Foxg1, involved in both primary specification of positional information and fine control of neural precursors kinetics.…”

Quand la migration de neurones signalisateurs contrôle la régionalisation du cortex cérébral

“…Récem-ment, un rôle des entrées sensorielles en provenance du thalamus (projections thalamo-corticales 2 ) a pu être mis en évidence à des stades post-nataux. Il a ainsi été proposé que ces projections thalamo-corticales déterminent la distinction entre aires primaires et secondaires dans le cortex visuel et somatosensoriel 3 [1,2] [3]. Cependant, l'implication exclusive de signaux diffu-2 Le thalamus est une structure sous-corticale composée d'un ensemble de noyaux, certains d'entre eux recevant l'information provenant des récepteurs de différentes modalités sensorielles et projetant directement vers les aires corticales primaires.…”

“…Cependant, l'implication exclusive de signaux diffu-2 Le thalamus est une structure sous-corticale composée d'un ensemble de noyaux, certains d'entre eux recevant l'information provenant des récepteurs de différentes modalités sensorielles et projetant directement vers les aires corticales primaires. 3 Traitant les informations provenant de la surface du corps (toucher, température, etc.). sant à partir d'une source focale apparaît difficilement compatible avec l'augmentation de la taille du cortex au cours de l'évolution des mammifères [4].…”