Molecular insights into the stress response of cnidarians with a focus on wound healing in the sea anemone nematostella vectensis and the coral Pocillopora damicornis

Thesis (Ph.D.)--Boston UniversityPLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Coral reefs are the foundation of many ocean ecosystems and coastal economies. Despite this, corals face intensifying anthropogenic threats, including pollution, dredging, destructive fishing practices, escalating sea surface temperatures, and ocean acidification. These insults render corals susceptible to disease, bleaching and algal over-growth. Given the rapid and widespread decline of coral, there is a pressing need to identify the stressors that are impacting corals and develop reliable prognoses for affected coral populations. With the long-range goal of developing more powerful tools for coral conservation, this dissertation is broadly aimed at understanding the molecular basis of stress response in cnidarians by (1) developing the coral Pocillopora damicornis into a model system and helping to create a publicly assessable database; (2) developing genomic resources for characterizing the expression of "response genes"; and (3) evaluating the response of corals to stress at the organismal, molecular, and transcriptomic levels. The focus has been on wound healing, a stress that corals deal with on a daily basis. How a coral survives and heals from these events is not understood at a molecular level. Using homology-based searches of genomic and transcriptomic datasets, putative wound-healing genes have been identified in the coral Pocillopora damicornis and the sea anemone, Nematostella vectensis . Also characterized are the molecular evolution and wound-induced expression of the transcription factor Grainyhead (Grh), a gene required for the reestablishment of the epithelial barrier following wounding in triploblasts. It is shown that the motif architecture of the Grh protein was established prior to the evolutionary split between cnidarians and triploblastic animals, and that Grh transcripts are up-regulated at the site of epithelial wounds in these cnidarians. These findings suggest that Grh's conserved role in epithelial wound healing predated the split between diploblasts and triploblasts. Finally, a protocol is developed for inducing minor wounds in Pocillopora , and the wound-healing process in 30 colony fragments was monitored over 45 days. Pocillopora RNA was isolated at 0, 6, 24, and 48 hour intervals following wounding for "deep sequencing" to establish a transcriptomic profile of the wound healing process.2031-01-0