PUBLICATION

Differential actinodin1 regulation in zebrafish and mouse appendages

Authors
Lalonde, R.L., Moses, D., Zhang, J., Cornell, N., Ekker, M., Akimenko, M.A.
ID
ZDB-PUB-160520-2
Date
2016
Source
Developmental Biology   417(1): 91-103 (Journal)
Registered Authors
Akimenko, Marie-Andree, Ekker, Marc, Zhang, Jing
Keywords
none
MeSH Terms
  • Animal Fins/embryology*
  • Animal Fins/metabolism
  • Animals
  • Animals, Genetically Modified
  • Binding Sites/genetics
  • Biological Evolution
  • Extremities/embryology*
  • Extremities/physiology
  • Gene Expression Regulation, Developmental
  • Limb Buds/growth & development
  • Limb Buds/metabolism
  • Mesoderm/cytology*
  • Mice
  • Morphogenesis/physiology
  • Promoter Regions, Genetic/genetics
  • Zebrafish/embryology*
  • Zebrafish Proteins/genetics*
PubMed
27196393 Full text @ Dev. Biol.
Abstract
The fin-to-limb transition is an important evolutionary step in the colonization of land and diversification of all terrestrial vertebrates. We previously identified a gene family in zebrafish, termed actinodin, which codes for structural proteins crucial for the formation of actinotrichia, rigid fibrils of the teleost fin. Interestingly, this gene family is absent from all tetrapod genomes examined to date, suggesting that it was lost during limb evolution. To shed light on the disappearance of this gene family, and the consequences on fin-to-limb transition, we characterized actinodin regulatory elements. Using fluorescent reporters in transgenic zebrafish, we identified tissue-specific cis-acting regulatory elements responsible for actinodin1 (and1) expression in the ectodermal and mesenchymal cell populations of the fins, respectively. Mutagenesis of potential transcription factor binding sites led to the identification of one binding site crucial for and1 expression in ectodermal cells. We show that these regulatory elements are partially functional in mouse limb buds in a tissue-specific manner. Indeed, the zebrafish regulatory elements target expression to the dorsal and ventral ectoderm of mouse limb buds. Absence of expression in the apical ectodermal ridge is observed in both mouse and zebrafish. However, cells of the mouse limb bud mesoderm do not express the transgene, in contrast to zebrafish. Altogether these results hint for a change in regulation of and1 during evolution that led to the downregulation and eventual loss of this gene from tetrapod genomes.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping