Mammals, including humans, cannot regrow lost or damaged body parts. Echinoderms, with whom mammals share a deep common ancestor, can quickly and efficiently regenerate numerous body parts including muscular, skeletal, soft, and nervous tissues of appendages and internal organs. The ability of echinoderms to regenerate makes these animals particularly attractive for research in regenerative medicine. However, studies of regeneration in echinoderms has lagged behind other model systems due to the lack of functional genomic tools. Thus our overarching goal is to develop echinoderm model systems for regenerative medicine. To this end, the first aim of this proposal is to finish and annotate the genomes of two echinoderm species that have served as proven models for studies of regeneration, including the sea cucumber, Sclerodactyla briareus, and the brittle star, Ophioderma brevispinum. Taken together, these organ- isms exhibit a broad spectrum of regenerative phenomena ranging from morphallactic remodeling through transdifferentiation of the existing tissues, to rapid epimorphic terminal growth. In particular, both animals can regrow their central nervous system. The second aim of our proposal is to adapt modern techniques of functional genomics to studies of adult echinoderm tissues. One sub-Aim here is to be able to experimentally regulate expression of genes of interest in vivo in regenerating animals. The focus of this sub-Aim will be electroporation and viral vector-based delivery of expression constructs into adult echinoderm tissues. Another sub-Aim is to use CRISPR/Cas9 genome editing technology in adult echinoderm tissues in vivo. In order to as- sess the efficiency of these functional genomic tools, we will use them to perturb transcription factors that are key regulators of echinoderm neurogenesis. Suppression of expression of these transcription factors is therefore expected to produce a clear phenotype by impairing neural regeneration in both species. The completion of the proposed project will lead to establishment of genomic resources to probe the functional role of known developmental genes, as well as of novel regeneration-associated genes identified in recent high-throughput expression studies, in the spontaneously regenerating cen- tral nervous system. This, in turn, will yield novel insights into the mechanisms of post-traumatic neurogenesis and inform the development of new therapeutic approaches to treat the poorly regener- ating neural injuries in human patients. The research agenda of the proposed project provides a wealth of opportunities. Many of our un- dergraduate and graduate students are the first in their families to have higher education opportunities and these students include many from historically under-represented minority groups.


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