Emx1 Is Required for Neocortical Area Patterning.

Adam M Stocker,Dennis D M O’Leary,Moises Mallo

doi:10.1371/journal.pone.0149900

Abstract

Establishing appropriate area patterning in the neocortex is a critical developmental event, and transcription factors whose expression is graded across the developing neural axes have been implicated in this process. While previous reports suggested that the transcription factor Emx1 does not contribute to neocortical area patterning, those studies were performed at perinatal ages prior to the emergence of primary areas. We therefore examined two different Emx1 deletion mouse lines once primary areas possess mature features. Following the deletion of Emx1, the frontal and motor areas were expanded while the primary visual area was reduced, and overall the areas shifted posterio-medially. This patterning phenotype was consistent between the two Emx1 deletion strategies. The present study demonstrates that Emx1 is an area patterning transcription factor and is required for the specification of the primary visual area.

Highlights

The neocortex is organized in the tangential domain into distinct functional fields, or areas, each of which area is responsible for processing modality specific information relayed from the periphery [1]
This study examined neocortical area patterning changes following Emx1 deletion
While previous studies have attempted to determine if Emx1 participates in area patterning [16,22,24], all of these studies were limited in scope because they were undertaken at perinatal time points

Summary

Introduction

The neocortex is organized in the tangential domain into distinct functional fields, or areas, each of which area is responsible for processing modality specific information relayed from the periphery [1]. Among the key events in neural development is the specification of distinct functional areas within the neocortex; a process called neocortical area patterning [2,3,4,5]. Neocortical area patterning begins early in cortical development and is controlled by the interplay of intrinsic genetic regulation and extrinsic subcortical innervation. Intrinsic regulation of neocortical patterning is characterized by transcription factors (TFs) expressed in neural progenitors in gradients along the medial-lateral and anterior-posterior axis [2,5]. Most of these TFs are in turn modulated and established by morphogens [3,4]. The TFs are expressed in neural progenitors early in neurogenesis, and most have maintained expression throughout neurogenesis [2,4]

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Results

Conclusion