The cortical hem regulates the size and patterning of neocortex

Giuliana Caronia-Brown, Michio Yoshida, Forrest Gulden, Stavroula Assimacopoulos, Elizabeth A. Grove

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

The cortical hem, a source of Wingless-related (WNT) and bone morphogenetic protein (BMP) signaling in the dorsomedial telencephalon, is the embryonic organizer for the hippocampus. Whether the hem is a major regulator of cortical patterning outside the hippocampus has not been investigated. We examined regional organization across the entire cerebral cortex in mice genetically engineered to lack the hem. Indicating that the hem regulates dorsoventral patterning in the cortical hemisphere, the neocortex, particularly dorsomedial neocortex, was reduced in size in latestage hem-ablated embryos, whereas cortex ventrolateral to the neocortex expanded dorsally. Unexpectedly, hem ablation also perturbed regional patterning along the rostrocaudal axis of neocortex. Rostral neocortical domains identified by characteristic gene expression were expanded, and caudal domains diminished. A similar shift occurs when fibroblast growth factor (FGF) 8 is increased at the rostral telencephalic organizer, yet the FGF8 source was unchanged in hem-ablated brains. Rather we found that hemWNT or BMP signals, or both, have opposite effects to those of FGF8 in regulating transcription factors that control the size and position of neocortical areas. When the hem is ablated a necessary balance is perturbed, and cerebral cortex is rostralized. Our findings reveal a much broader role for the hem in cortical development than previously recognized, and emphasize that two major signaling centers interact antagonistically to pattern cerebral cortex.

Original languageEnglish (US)
Pages (from-to)2855-2865
Number of pages11
JournalDevelopment (Cambridge)
Volume141
Issue number14
DOIs
StatePublished - Jul 2014

Keywords

  • Embryonic patterning
  • Fgf8
  • Mouse
  • Neocortex
  • Signaling center
  • Wnt3a

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

Fingerprint

Dive into the research topics of 'The cortical hem regulates the size and patterning of neocortex'. Together they form a unique fingerprint.

Cite this