Based primarily on DNA and RNA sequencing, genes encoding proteins in the NF-κB signaling pathway have been discovered in a variety of early-branching organisms. Although knowledge of the evolution of NF-κB signaling and the immune system continues to grow, many gaps remain in our understanding of relevant complex gene regulatory networks and biological processes regulated by NF-κB in most basal animals. In this thesis, NF-κB signaling is characterized in the sea anemone Nematostella vectensis, a commonly used model in the phylum Cnidaria. By RNA-seq analysis, a positive correlation between nutrition and immunity is shown in Nematostella. Gene expression profiling of adult fed and starved anemones showed that starvation led to the downregulation of many genes involved in nutrient metabolism, cellular respiration, and immune and defense responses. Starved adult anemones also had reduced protein levels and DNA-binding activity of immunity-related transcription factor NF-κB, which was observed as early as two weeks of starvation and as late as two months. Starved juvenile anemones had increased sensitivity to bacterial infection and also had lower NF-κB protein levels, as compared to fed controls. Weighted Gene Correlation Network Analysis (WGCNA) identified significantly correlated gene networks that were downregulated following starvation, and also identified candidate NF-κB target genes. Previous work has shown that NF-κB signaling plays a role in Nematostella development, however, little is known about the role NF-κB may play as part of the cnidarian immune response. CRISPR/Cas9 technology was used in an attempt to genetically disrupt NF-κB function in Nematostella. In preliminary results, it is shown that CRISPR/Cas9 injection of fertilized eggs resulted in a mosaic alteration of DNA sequences in the Nematostella NF-κB gene. Mating of these mosaic animals generated heterozygous anemones with minor genomic DNA alterations of the NF-κB gene. Continuing efforts are directed towards generating and characterizing CRISPR-induced loss-of-function mutations of NF-κB to serve as tools for future research into the evolution of NF-κB signaling and regulated immunity. Together, these results demonstrate a correlation between nutrition and immunity in an early-diverged marine metazoan, and results have implications for the health of marine organisms as they encounter changing environments.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/47475 |
| Date | 07 November 2023 |
| Creators | Aguirre Carrion, Pablo Joshua |
| Contributors | Gilmore, Thomas D. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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