A new catalogue of genomic data for the axolotl, an odd amphibian that can regrow its limbs, has now been made available to researchers. A team of scientists created a nearly complete list of the axolotl genome and pinpointed genes of interest—including genes linked to limb regeneration. The findings are in a paper that was just published in the journal Cell Reports.
Axolotls (Ambystoma mexicanum) are neotenic salamanders, animals that retain some of their larval stage traits and abilities. Unlike other salamanders, axolotls never leave the water, keep their gills, and stay fully aquatic. They are native to Mexico but have become popular aquarium pets. The most unique ability of the axolotl is the ability to regrow their limbs—even if the limb has been completely removed. They can also regenerate other parts of their body; there are a few cases of axolotls re-growing eyes and parts of the brain. This makes them very interesting to scientists, especially those working in the medical field. A better understanding of these regeneration mechanisms could lead to new medical treatments for humans.
Researchers from the Brigham and Women’s Hospital studied various types of tissue in axolotls, slowly piecing together a comprehensive list of their genes. While there have been similar studies conducted in the past, this is now the most complete transcriptome (another word for a reference catalogue of genes) for the axolotl. The team’s study also includes a number of genes of interest, including genes that play important roles in limb regeneration. For example, the research team identified a gene called kazald1 which is primarily expressed during embryonic development. When the researchers deactivated the gene, the axolotls were unable to properly re-grow amputated limbs. A protein called cirbp also appeared to play a major role in regeneration. By studying these genes, scientists will gain new insights into how the salamanders manage to regenerate limbs so quickly.
The team’s new genomic database for axolotls will be available publicly so that other researchers can use it in future studies. The authors hope that their transcriptome will be a valuable resource for studying the mechanisms of limb regeneration.
Bryant et al. A Tissue-Mapped Axolotl De Novo Transcriptome Enables Identification of Limb Regeneration Factors. Cell Reports (2017).