CAREER: From novel proteins to novel organelles, construction of the cnidarian stinging apparatus

About This Grant

The emergence of novel traits – traits that are unique to a group of organisms – is an important driver of organismal diversity, yet our understanding of how novel traits arise is still in its infancy. Nematocytes, the stinging cells found only in cnidarians (corals, jellyfish, and their relatives), are an important model for understanding the origin of novelty. Nematocytes derive their sting from their ability to eject a tiny, venom-laden harpoon from a pressurized compartment inside a cell. The compartment, and the harpoon it contains, are constructed of an unusual protein called minicollagen, which is also found only in cnidarians. Recent advances in genome sequencing have greatly improved our ability to detect novel protein-coding sequences from DNA; still, there remains a critical gap in our understanding of how novel proteins (like minicollagen) give rise to novel traits (like the nematocyte). To address this gap, the proposed work is characterizing the protein-protein interactions necessary for the development of the stinging apparatus in diverse types of nematocytes. Additionally, to understand how novel protein-coding sequences acquire adaptive functions, this work is investigating the processes that direct proteins to their proper locations inside the cell. Ultimately, these investigations will enable the development of designer cells with traits that have never come together naturally. The educational goal of this research is to better prepare undergraduate students to pursue careers in integrative research through development of a research-based lab course in evolutionary cell biology. This research is also increasing public science literacy by providing new and innovative learning resources to STEM educators and museum visitors. The overarching goal of this work is to develop a framework for predicting the emergence of novel traits from novel protein-coding genes by investigating the processes that drove the emergence of the nematocyte. To achieve this goal, the proposed work is using mass spectroscopy and proteomic analysis to characterize how unique nematocyte types emerge from taxon-specific interactions among novel proteins (Aim 1). Additionally, using genome engineering to alter protein localization, the proposed work is reconstructing the order of events that permitted the fixation of the nematocyte-specific protein minicollagen in the stem cnidarian genome (Aim 2). Collectively, this work is revealing how functional interactions among novel proteins drive the emergence of novel traits. This work will advance our ability to predict the fate of novel proteins and contribute significantly to explaining cases of novelty that arise de novo from new genes. 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.