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Expression of Fluorescent Proteins in Branchiostoma lanceolatum by mRNA Injection into Unfertilized Oocytes
Published on: January 12, 2015
Conservation of amelogenin gene expression during tetrapod evolution.
Nathalie Assaraf-Weill1, Barbara Gasse, Nawfal Al-Hashimi
1UMR 7138, Research Group "Evolution and Development of the Skeleton", Université Pierre et Marie Curie, Paris, France.
Summary
Amelogenin (AMEL) gene expression in salamanders shows conserved patterns in ameloblasts across development, similar to mammals and reptiles. This suggests AMEL
Area of Science:
- Evolutionary developmental biology (Evo-Devo)
- Molecular biology
- Comparative genomics
Background:
- Amelogenesis, the process of enamel formation, is well-understood in mammals but less so in amphibians and reptiles.
- Amelogenin (AMEL) is a key enamel matrix protein (EMP) crucial for enamel structure.
- Understanding AMEL evolution and expression in diverse tetrapods provides insights into enamel evolution.
Purpose of the Study:
- To investigate the molecular evolution and gene expression of amelogenin (AMEL) in the amphibian salamander, Pleurodeles waltl.
- To correlate changes in AMEL protein sequences with its temporospatial gene expression during amelogenesis using an evo-devo approach.
- To compare AMEL expression patterns in amphibians with those in reptiles and mammals.
Main Methods:
- RNA extraction from salamander lower jaws.
- Polymerase Chain Reaction (PCR) and Rapid Amplification of Complementary DNA Ends (RACE PCR) to obtain the AMEL sequence.
- Sequence alignment of P. waltl AMEL with other tetrapod sequences.
- In situ hybridization using sense and anti-sense probes on developmental stages (larvae, juveniles, adults).
Main Results:
- The P. waltl AMEL sequence exhibited conserved N- and C-terminal regions with a highly variable central region compared to other tetrapods.
- AMEL gene expression was consistently localized to ameloblasts throughout ontogeny.
- The expression pattern of AMEL remained conserved across different developmental stages, including those with both enamel and enameloid.
- Observed expression patterns in salamanders were similar to those previously described in lizards and mammals.
Conclusions:
- Despite significant variations in its central region, the temporospatial expression of AMEL has remained remarkably conserved during tetrapod evolution over 360 million years.
- The conserved expression pattern of AMEL suggests a fundamental role in amelogenesis that predates the divergence of major tetrapod lineages.
- This study highlights the utility of evo-devo approaches in understanding the evolutionary constraints and conserved mechanisms of key developmental genes.
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