Meeting Abstract
Much of metazoan morphological diversity is due to dynamic expression of transcription factor networks in development. Despite this remarkable diversity, animal development is accomplished by relatively few, related transcription factor families. The evolution of these gene regulatory networks remains poorly understood. How networks assemble in association with a particular phenotype, how changes to these networks alter phenotype in evolution, and how networks are coopted into new traits are fundamental unanswered questions in biology. It has been difficult to address questions like these due to a lack of functional evidence for particular network-phenotype associations in multiple animal lineages, and for distinct phenotypic associations within a single species. The retinal determination network (RDN) specifies eye cell fates in Drosophila and vertebrates, comprised of the core genes: Pax, Six, Dach, and Eya. These genes have well-understood regulatory relationships in eye development. Members of this network are expressed in association with photoreceptive tissue in many animal lineages, and the RDN is found in multiple other phenotypic contexts. However it is not clear if this gene network evolved with the origin of visual systems or in another phenotypic context then later was co-opted into visual system development. Our goal is to understand the regulatory state of the RDN in the sea anemone Nematostella vectensis and its functional relationship to cell fate. We use a combination of CRISPR knockouts and shRNA knockdown experiments followed by in situ hybridization and real time quantitative PCR to functionally interrogate the network hierarchy and its relationship to cell type development. This genetic analysis in a basal eumetazoan is necessary for understanding how gene networks evolve and bring about phenotypic change.
