Disruption of SoxB1-dependent Sonic hedgehog expression in the hypothalamus causes septo-optic dysplasia

Dev Cell. 2012 Mar 13;22(3):585-96. doi: 10.1016/j.devcel.2011.12.023.

Abstract

Septo-optic dysplasia (SOD) is a congenital brain anomaly that results in pituitary, optic nerve, and midline forebrain defects. The etiology of SOD is poorly understood, with the majority of cases being sporadic. In rare instances, SOD is caused by mutations in Sox2, Sox3, or Hesx1, but how this manifests in disease is not entirely certain. We demonstrate here that mouse embryos lacking Sonic hedgehog (Shh) in the prospective hypothalamus exhibit key features of SOD, including pituitary hypoplasia and absence of the optic disc. The hypothalamic source of Shh is required to maintain gene expression boundaries along the anteroposterior and mediolateral neural axes that are important for proper pituitary and eye development, respectively. We further reveal that Sox2 and Sox3 are dose-dependent regulators of Shh transcription that directly bind and activate a long-range Shh forebrain enhancer. These data indicate that reduced levels of Shh expression in the hypothalamus cause SOD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Female
  • Hedgehog Proteins / genetics
  • Hedgehog Proteins / metabolism*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Hypothalamus / embryology
  • Hypothalamus / growth & development
  • Hypothalamus / metabolism
  • Male
  • Mice
  • Mice, Transgenic
  • Prosencephalon / growth & development
  • Prosencephalon / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • SOXB1 Transcription Factors / genetics
  • SOXB1 Transcription Factors / metabolism*
  • Septo-Optic Dysplasia / genetics
  • Septo-Optic Dysplasia / metabolism*

Substances

  • Hedgehog Proteins
  • Hesx1 protein, mouse
  • Homeodomain Proteins
  • Repressor Proteins
  • SOXB1 Transcription Factors
  • Shh protein, mouse
  • Sox2 protein, mouse
  • Sox3 protein, mouse