A cis-regulatory change underlying the motor neuron-specific loss of Ebf expression in immotile tunicate larvae

Elijah K. Lowe, Claudia Racioppi, Nadine Peyriéras, Filomena Ristoratore, Lionel Christiaen, Billie J. Swalla, Alberto Stolfi

Research output: Contribution to journalArticlepeer-review


Many species in the tunicate family Molgulidae have independently lost their swimming larval form and instead develop as tailless, immotile larvae. These larvae do not develop structures that are essential for swimming such as the notochord, otolith, and tail muscles. However, little is known about neural development in these nonswimming larvae. Here, we studied the patterning of the Motor Ganglion (MG) of Molgula occulta, a nonswimming species. We found that spatial patterns of MG neuron regulators in this species are conserved, compared with species with swimming larvae, suggesting that the gene networks regulating their expression are intact despite the loss of swimming. However, expression of the key motor neuron regulatory gene Ebf (Collier/Olf/EBF) was reduced in the developing MG of M. occulta when compared with molgulid species with swimming larvae. This was corroborated by measuring allele-specific expression of Ebf in hybrid embryos from crosses of M. occulta with the swimming species M. oculata. Heterologous reporter construct assays in the model tunicate species Ciona robusta revealed a specific cis-regulatory sequence change that reduces expression of Ebf in the MG, but not in other cells. Taken together, these data suggest that MG neurons are still specified in M. occulta larvae, but their differentiation might be impaired due to reduction of Ebf expression levels.

Original languageEnglish (US)
Pages (from-to)72-85
Number of pages14
JournalEvolution and Development
Issue number2
StatePublished - Mar 2021


  • Cis-regulatory changes
  • Collier/Olf/EBF
  • Molgula
  • evolutionary loss
  • motor neurons
  • tunicates

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Developmental Biology


Dive into the research topics of 'A cis-regulatory change underlying the motor neuron-specific loss of Ebf expression in immotile tunicate larvae'. Together they form a unique fingerprint.

Cite this