ZFIN ID: ZDB-PUB-111011-18
Subnuclear development of the zebrafish habenular nuclei requires ER translocon function
Doll, C.A., Burkart, J.T., Hope, K.D., Halpern, M.E., and Gamse, J.T.
Date: 2011
Source: Developmental Biology   360(1): 44-57 (Journal)
Registered Authors: Doll, Caleb, Gamse, Josh, Halpern, Marnie E.
Keywords: neurogenesis, left-right assymetry, epithalamus, endoplasmic reticulum
MeSH Terms:
  • Animals
  • Base Sequence
  • Body Patterning/genetics
  • Body Patterning/physiology
  • DNA Primers/genetics
  • Endoplasmic Reticulum/physiology
  • Habenula/cytology
  • Habenula/embryology*
  • Habenula/physiology
  • Membrane Proteins/genetics*
  • Membrane Proteins/physiology*
  • Models, Neurological
  • Mutation
  • Neurogenesis/genetics
  • Neurogenesis/physiology
  • Neurons/cytology
  • Nodal Signaling Ligands/genetics
  • Nodal Signaling Ligands/physiology
  • Phenotype
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish/physiology
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/physiology*
PubMed: 21945073 Full text @ Dev. Biol.

The dorsal habenular nuclei (Dh) of the zebrafish are characterized by significant left–right differences in gene expression, anatomy, and connectivity. Notably, the lateral subnucleus of the Dh (LsDh) is larger on the left side of the brain than on the right, while the medial subnucleus (MsDh) is larger on the right compared to the left. A screen for mutations that affect habenular laterality led to the identification of the sec61a-like 1(sec61al1) gene. In sec61al1c163 mutants, more neurons in the LsDh and fewer in the MsDh develop on both sides of the brain. Generation of neurons in the LsDh occurs more rapidly and continues for a longer time period in mutants than in WT. Expression of Nodal pathway genes on the left side of the embryos is unaffected in mutants, as is the left sided placement of the parapineal organ, which promotes neurogenesis in the LsDh of WT embryos. Ultrastructural analysis of the epithalamus indicates that ventricular precursor cells, which form an epithelium in WT embryos, lose apical-basal polarity in sec61al1c163 mutants. Our results show that in the absence of sec61al1, an excess of precursor cells for the LsDh exit the ventricular region and differentiate, resulting in formation of bilaterally symmetric habenular nuclei.