In the spring of 2023 I completed research on the formation of the neural crest in the non-vertebrate chordate Ciona robusta. 

The neural crest in vertebrates is vital for the development of the embryo. In tunicates such as Ciona robusta, we can see the migration of neural crest cells (NCCs) throughout the neuronal development. This organism was picked specifically for their bipolar tail neuron, mirrored to the dorsal root ganglia found in humans and other vertebrates. 

In a paper published in 2020 by the Stolfi lab at the Georgia Institute of Technology, it was found that there were many genes associated with the production of neurogenin. My team decided to focus on two of the genes with the most activity: DCLK and EMX. 

The DCLK gene encodes a cytoplasmic protein that is responsible for the binding of microtubules in the cortex. DCLK may also play a role in neuronal development and cellular organization across the neural crest. EMX may make the development of the bipolar tail neuron greatly reduced. It is hypothesized that DCLK and EMX disregulate EMX and express DCLK within the bipolar tail neuron development and neural crest cell formation of C. robusta. 

The DCLK gene was over expressed between introns 2 and three.

DCLK gene model identifies regions of interest for potential intronic BTN enhancers. Credit: Solfi and Pilger lab

We focused on what causes the development of the bipolar tail neuron in C. robusta. My team inserted fluorescent reporters using electroporation in C. robusta embryos. While we found that the over-expression in DCLK did not have much of an effect on the bipolar tail neuron. What we did find was that the motor ganglion was greatly affected.

Activity in the motor ganglion following electroporation. Credit: Stolfi and Pilger lab

The EMX knockout did not seem to have an effect on the expression of neurogenin.

Later research plans are to explore why DCLK had an effect on the motor ganglion as well as the full effects of the EMX knockout on intron 1.

I would like to thank Dr. John Pilger at Agnes Scott College, Sydney Popsuj, and the Stolfi Lab at Georgia Institute of Technology for allowing me to partake in this research.

Works Cited:

  • Kim, K., Gibboney, S., Razy-Krajka, F., Lowe, E. K., Wang, W., & Stolfi, A. (2020). Regulation of neurogenesis by FGF signaling and neurogenin in the invertebrate chordate Ciona. Frontiers in Cell and Developmental Biology, 8. https://doi.org/10.3389/fcell.2020.00477
  • Abitua, P. B., Wagner, E., Navarrete, I. A., & Levine, M. (2012). Identification of a rudimentary neural crest in a non-vertebrate chordate. Nature, 492(7427), 104–107. https://doi.org/10.1038/nature11589
  • Kim, K., Orvis, J., & Stolfi, A. (2022). Pax3/7 regulates neural tube closure and patterning in a non-vertebrate chordate. Frontiers in cell and developmental biology, 10, 999511. https://doi.org/10.3389/fcell.2022.999511
Scientific poster presented at SpARCDownload