Meeting Abstract
The class IV POU (pou-iv, or brn-3) gene encodes a homeodomain transcription factor that evolved at or near the base of the animal tree. pou-iv genes regulate sensory cell subtype differentiation and maintenance in bilaterian models (e.g. inner ear hair cells and retinal ganglion cells in vertebrates), and their cnidarian ortholog is expressed in a subset of differentiating and differentiated sensory cells in jellyfish, suggestive of a deeply conserved role of POU-IV in regulating sensory cell differentiation. However, mechanistic understanding of how POU-IV regulates neural differentiation and maintenance is wanting in Cnidaria, and thus fundamentally conserved transcriptional control mechanisms underlying these processes remain enigmatic. To address this baseline knowledge gap, I am investigating the molecular mechanisms by which POU-IV specifies and maintains neural subtypes in the sea anemone cnidarian Nematostella vectensis. Preliminary gene expression analyses by in situ hybridization and immunostaining with an antibody against N. vectensis POU-IV show that POU-IV is specifically expressed in neurons in N. vectensis, consistent with the hypothesis that POU-IV plays a role in neural development and maintenance in N. vectensis. I am directly testing this hypothesis by taking a CRISPR-Cas9-mediated gene knockout approach. Comparison of the results of these analyses with existing data from bilaterian models is expected to reveal a deeply conserved mechanism that confers, and maintains, neural subtype identities in animals.
