Transcription Factors in Cnidarian Immunity, Symbiosis, and Bleaching

Trustees Of Boston University, Boston

Investigators

Abstract

The research to be carried out in this project will provide increased knowledge of the molecular factors (genes and proteins) that are involved in immunity and stress responses in a group of natural and model marine organisms, including corals and sea anemones. This project will investigate the role of a cellular transcription factor, NF-kappaB, which is important for immunity. The research will identify genes that are activated by NF-kappaB when an algal symbiont is removed from its host coral or when coral is stressed by bleaching. This information will be helpful in understanding how corals and sea anemones are affected by changes in their environments. It will also identify how the algal symbiont of a coral helps the coral stay healthy. Finally, it will enhance the understanding of the NF-kappaB protein, which is a highly conserved protein and important for immunity in other animals, including humans. Thus, these results could also lead to new insights with implications for human health. The interdisciplinary research team comprises a junior scientist with expertise in areas of marine ecology and gene expression and a senior scientist with expertise in molecular pathway analysis. In addition, the research will provide training to students (especially undergraduate and graduate students) who will be able to pursue careers in related areas in academia, the private sector, or government. This research will further the understanding of molecular processes that regulate a key symbiosis, and how disruption of those processes can lead to dysbiosis. The marine symbiosis to be studied is that which occurs between certain cnidarian hosts (sea anemones and corals) and algae of the family Symbiodiniaceae. Specifically, this research will provide insights into the function of NF-kappaB and other signaling pathways in cnidarian immunity, and the biological significance of modulation of NF-kappaB and other transcription factors for cnidarian-algal symbiosis. The conserved NF-kappaB transcription factor controls innate immune and stress responses in a variety of organisms. NF-kappaB carries out its biological effects by regulating the expression of genes that program relevant biological responses. As such, three major experimental goals will be addressed. (1) To identify target genes of NF-kappaB that are affected by loss of symbiosis in laboratory controlled experiments in the sea anemone model Aiptasia, as well as the regulation of NF-kappaB by internal and external cues. (2) Using a novel high-throughput approach, additional transcription factors altered by loss of symbiosis in Aiptasia will also be identified. (3) The effects of the establishment and loss of symbiosis on NF-kappaB, and other signaling pathways in corals, using laboratory and field collected specimens, will also be pursued. The research will enhance the understanding of the evolutionary underpinnings of a key signal transduction pathway (NF-kappaB), its role in symbiosis, and how such signaling pathways can direct biological outcomes in response to environmental changes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.