Activity of dlx5a/dlx6a regulatory elements during zebrafish GABAergic neuron development

Yu, M., Xi, Y., Pollack, J., Debiais-Thibaud, M., Macdonald, R.B., and Ekker, M.
International journal of developmental neuroscience : the official journal of the International Society for Developmental Neuroscience   29(7): 681-91 (Journal)
Registered Authors
Debiais-Thibaud, Mélanie, Ekker, Marc, MacDonald, Ryan, Xi, Yanwei
cis-regulatory elements, dix genes, forebrain, GABAergic neuron, gene regulation, transgenesis, zebrafish, danio rerio
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Brain/cytology
  • Brain/growth & development
  • Brain/metabolism
  • GABAergic Neurons/cytology
  • GABAergic Neurons/physiology*
  • Gene Expression Regulation, Developmental
  • Homeodomain Proteins/genetics
  • Homeodomain Proteins/metabolism*
  • In Situ Hybridization
  • Mice
  • Recombinant Fusion Proteins/genetics
  • Recombinant Fusion Proteins/metabolism
  • Regulatory Sequences, Nucleic Acid*
  • Transcription Factors/genetics
  • Transcription Factors/metabolism*
  • Transgenes
  • Zebrafish/anatomy & histology*
  • Zebrafish/embryology*
  • Zebrafish/growth & development*
  • Zebrafish/metabolism
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
21723936 Full text @ Int. J. Dev. Neurosci.
During vertebrate forebrain formation, Dlx homeobox genes play essential roles in the differentiation, migration and survival of subpallial precursor cells that will later give rise to diverse subtypes of γ-aminobutyric acid (GABA)-expressing neurons, including inhibitory cortical interneurons in mammals. They also participate in the regulation of the Gad genes encoding the enzymes necessary for GABA synthesis. In mice, at least four cis-regulatory elements (CREs) control Dlx expression in the telencephalon and diencephalon: URE2 and I12b in the Dlx1/Dlx2 bigene cluster, and I56i and I56ii in the Dlx5/Dlx6 bigene cluster. However, little is known so far with respect to the function of orthologous dlx genes and their regulatory elements during zebrafish GABAergic neuron development. To investigate whether similar dlx-mediated pathways exist in the early developing zebrafish forebrain, we generated independent lines of transgenic zebrafish carrying two distinct GFP reporter constructs driven by a β-globin minimal promoter: one containing a not, vert, similar1.4 kb dlx5a/dlx6a intergenic sequence (encompassing I56i and I56ii) and one with a not, vert, similar1.1 kb fragment containing only the I56i CRE, respectively. The expression patterns of these two transgenes were compared with that obtained with another construct containing the not, vert, similar1.4 kb dlx5a/dlx6a intergenic sequence and driven by a not, vert, similar3.5 kb dlx6a 52-flanking fragment. Our comparative analysis showed that GFP expression of the three transgene is largely overlapping throughout the ventral forebrain. Intriguingly, the dlx6a 52-flanking fragment has a major impact on transgene expression in the mesencephalic tectum. Furthermore, comparison of transgene expression between the not, vert, similar1.4 kb and not, vert, similar1.1 kb intergenic fragments did not show any specific spatial expression conferred by I56ii. Almost all GFP-expressing cells in the transgenic zebrafish are GABA-positive and also express various GABAergic interneuron markers. Together, our data suggest that zebrafish dlx5a/dlx6a intergenic CREs may be involved in a conserved genetic pathway necessary for proper dlx expression during zebrafish GABAergic neuron development.
Genes / Markers
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes