ZFIN ID: ZDB-PUB-080902-9
Gsk3{beta}/PKA and Gli1 regulate the maintenance of neural progenitors at the midbrain-hindbrain boundary in concert with E(Spl) factor activity
Ninkovic, J., Stigloher, C., Lillesaar, C., and Bally-Cuif, L.
Date: 2008
Source: Development (Cambridge, England)   135(18): 3137-3148 (Journal)
Registered Authors: Bally-Cuif, Laure, Lillesaar, Christina, Ninkovic, Jovica, Stigloher, Christian
Keywords: E(Spl), Her5, Her11, Zebrafish, Midbrain-hindbrain boundary, Neural progenitor, Gsk3β, PKA, Gli1
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Basic Helix-Loop-Helix Transcription Factors/genetics
  • Basic Helix-Loop-Helix Transcription Factors/metabolism*
  • Cyclic AMP-Dependent Protein Kinases/genetics
  • Cyclic AMP-Dependent Protein Kinases/metabolism*
  • Embryo, Nonmammalian
  • Immunohistochemistry
  • In Situ Hybridization
  • Mesencephalon/embryology*
  • Mesencephalon/metabolism
  • Mesencephalon/physiology
  • Models, Biological
  • Nervous System/metabolism
  • Neurons/metabolism
  • Neurons/physiology*
  • Oncogene Proteins/genetics
  • Oncogene Proteins/metabolism*
  • Rhombencephalon/embryology*
  • Rhombencephalon/metabolism
  • Rhombencephalon/physiology
  • Stem Cells/cytology
  • Stem Cells/physiology*
  • Trans-Activators/genetics
  • Trans-Activators/metabolism*
  • Zebrafish/embryology
  • Zebrafish/genetics
  • Zebrafish/metabolism
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 18725518 Full text @ Development
FIGURES
ABSTRACT
Neuronal production in the midbrain-hindbrain domain (MH) of the vertebrate embryonic neural tube depends on a progenitor pool called the 'intervening zone' (IZ), located at the midbrain-hindbrain boundary. The progressive recruitment of IZ progenitors along the mediolateral (future dorsoventral) axis prefigures the earlier maturation of the MH basal plate. It also correlates with a lower sensitivity of medial versus lateral IZ progenitors to the neurogenesis inhibition process that maintains the IZ pool. This role is performed in zebrafish by the E(Spl) factors Her5 and Her11, but the molecular cascades cooperating with Her5/11, and those accounting for their reduced effect in the medial IZ, remain unknown. We demonstrate here that the kinases Gsk3beta and cAMP-dependent protein kinase A (PKA) are novel determinants of IZ formation and cooperate with E(Spl) activity in a dose-dependent manner. Similar to E(Spl), we show that the activity of Gsk3beta/PKA is sensed differently by medial versus lateral IZ progenitors. Furthermore, we identify the transcription factor Gli1, expressed in medial IZ cells, as an antagonist of E(Spl) and Gsk3beta/PKA, and demonstrate that the neurogenesis-promoting activity of Gli1 accounts for the reduced sensitivity of medial IZ progenitors to neurogenesis inhibitors and their increased propensity to differentiate. We also show that the expression and activity of Gli1 in this process are, surprisingly, independent of Hedgehog signaling. Together, our results suggest a model in which the modulation of E(Spl) and Gsk3beta/PKA activities by Gli1 underlies the dynamic properties of IZ maintenance and recruitment.
ADDITIONAL INFORMATION