Myotome segmentation during axolotl tail regeneration

Tissue patterning, the formation of specific body parts, is essential to eventually regenerate fully functional limbs and organs. Tissue patterning is well understood in the course of embryonic development, but less so in regeneration. In my research, I use the axolotl, a species of salamander. The axolotl has the capacity to grow back a fully patterned tail, a key element of forming the front-to-back axis, the primary body axis. I aim to interrogate if the mechanisms that are used to pattern the primary body axis during embryonic development are also used during regeneration of the tail. Patterning of the primary body axis is originally determined during early embryogenesis by the formation of discreet blocks of tissue along the primary body axis, termed somites. Somites are responsible for the patterning of muscle and vertebrae. Strangely, during regeneration the axolotl tail is correctly patterned in the absence of somites. The earliest structure that patterns in the regenerating tail is the muscle, followed by the vertebrae and other structures. I will study the segmentation and patterning of muscle during axolotl tail regeneration as a first entry point to understand patterning of the primary body axis during regeneration. The formation of somites is dependent on oscillatory gene expression. I will use gene expression analysis to determine if similar oscillatory expressions patterns can be observed during tail regeneration. I will label oscillatory genes fluorescently to visualise their oscillatory behaviour. I will also mutate the oscillatory genes to show their importance in patterning the regenerating tail. This work will use computer simulations and novel methods of gene expression analysis to predict and detect oscillatory genes. Due to recent advances in the Tanaka laboratory, including the comprehensive characterisation of the axolotl genome, these analyses are now possible. This work will provide insights as to how muscle patterning can occur during regeneration in adult organisms and provides a starting point to interrogate other aspects of axolotl tail regeneration, such as the patterning of vertebrae. Finally, it could also provide fundamental insights into principles which underlie patterning during development.