Researchers conducted single-cell gene expression analysis to uncover the effects of manipulation of the sensory cell regulator POU IV in the protovertebrate Ciona intestinalis. Alteration of POU IV expression led to the induction of cells with characteristics of multiple sensory cell types and cells that express a gene expression profile that has not been previously observed in Ciona intestinalis. The activation of upstream POU IV regulators Foxg and Neurogenin was identified as a possible mechanism underlying the unusual sensory cell development.