An element in the alpha1-tubulin promoter is necessary for retinal expression during optic nerve regeneration but not after eye injury in the adult zebrafish

Senut, M.C., Gulati-Leekha, A., and Goldman, D.
The Journal of neuroscience : the official journal of the Society for Neuroscience   24(35): 7663-7673 (Journal)
Registered Authors
Goldman, Dan
tubulin; gene expression; homeodomain; E-box; regeneration; retina; visual system; zebrafish
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • Axotomy
  • Cell Cycle
  • E-Box Elements/genetics*
  • Eye Proteins/biosynthesis
  • Eye Proteins/genetics*
  • Gene Expression Regulation/genetics*
  • Gene Expression Regulation, Developmental/genetics
  • Genes, Reporter
  • Green Fluorescent Proteins/biosynthesis
  • Green Fluorescent Proteins/genetics
  • Introns/genetics
  • Nerve Crush
  • Nerve Regeneration/genetics*
  • Nerve Tissue Proteins/biosynthesis
  • Nerve Tissue Proteins/genetics*
  • Neuroglia/metabolism
  • Optic Nerve Injuries/genetics*
  • Optic Nerve Injuries/metabolism
  • Promoter Regions, Genetic/genetics*
  • Recombinant Fusion Proteins/biosynthesis
  • Regeneration/genetics*
  • Retina/embryology
  • Retina/growth & development*
  • Retina/injuries
  • Retina/physiology
  • Retinal Ganglion Cells/metabolism
  • Sequence Deletion
  • Transcription, Genetic
  • Tubulin/biosynthesis
  • Tubulin/genetics*
  • Zebrafish
15342733 Full text @ J. Neurosci.
We have shown previously that a 1.696 kb upstream fragment of the goldfish alpha1-tubulin promoter was capable of driving green fluorescent protein (GFP) expression in the developing and regenerating zebrafish CNS in a pattern closely mimicking the endogenous alpha1-tubulin gene. Comparison of fish and rat alpha1-tubulin promoters identified a 64 bp region with a conserved repetitive homeodomain (HD) consensus sequence core (TAAT) and a nearby basic helix-loop-helix binding E-box sequence (CANNTG), which led us to speculate that it could be of importance for regulating alpha1-tubulin gene transcription. To address this issue, we examined the ability of deletion mutants of the 1.696 kb promoter to drive expression of GFP in zebrafish retinal cells under normal conditions and after injury. Interestingly, although wild-type 1.696 kb and mutant promoters, lacking the E-box and/or HD sequences, exhibited rather similar patterns of GFP expression in the developing retina, significant differences were noticed in the mature retina. First, although the 1.696 kb promoter directed transgene expression to retinal neurons and progenitor cells, the activity of mutant promoters was drastically reduced. Second, we found that the E-box and HD sequences were necessary for transgene reinduction during optic nerve regeneration, but were not as important for transgene expression in regenerating retinal neurons after eye injury. In this latter lesion model, remarkably, both 1.696 kb and mutant promoters targeted GFP expression to Muller glia-like cells, some of which re-entered the cell cycle. These new findings will be useful for identifying the molecular signals necessary for successful CNS regeneration.
Genes / Markers
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes