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ABSTRACT The ascidianBoytryllus schlosseriis a marine chordate that thrives under conditions of anthropogenic climate change. TheB. schlosseriexpressed proteome contains unusually high levels of proteins adducted with 4‐hydroxy‐2‐nonenal (HNE). HNE represents a prominent posttranslational modification resulting from oxidative stress. Prior to this study, which identified 1052 HNE adducted proteins inB. schlosseri byLCMS, HNE protein modification has not been determined in any marine species. Adducted residues were ascertained for 1849 HNE modifications, 1195 of which had a maximum amino acid localization score. Most HNE modifications were at less reactive lysines (rather than more reactive cysteines). HNE prevalence on most sites was high, suggesting thatB. schlosseriexperiences and tolerates high intracellular reactive oxygen species levels, resulting in substantial lipid peroxidation. HNE adductedB. schlosseriproteins show enrichment in mitochondrial, proteostasis, and cytoskeletal functions. We propose that redox signaling contributes to regulating energy metabolism, the blastogenic cycle, oxidative burst defenses, and cytoskeleton dynamics inB. schlosseri. DIA‐LCMS quantification of 72 HNE‐adducted sites across 60 proteins revealed significant population‐specific differences. We conclude that the vast amount of HNE protein adduction in this circumpolar tunicate is indicative of high oxidative stress tolerance contributing to its range expansion into diverse environments. SummaryOxidative stress results from environmental challenges that increase in frequency and severity during the Anthropocene.Oxygen radical attack causes lipid peroxidation, leading to HNE production.Proteome‐wide HNE adduction is highly prevalent inBotryllus schlosseri, a widely distributed, highly invasive, and economically important biofouling ascidian, and the first marine species to be analyzed for proteome HNE modification.HNE adduction of specific proteins may physiologically sequester reactive oxygen species, which could enhance fitness and resilience during environmental change.
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Proteome Dynamics Across the Blastogenic Cycle of Botryllus schlosseri Reveals Targets for Cell Immortalization
Abstract The colonial tunicateBotryllus schlosseriregenerates weekly through a cyclical process in which adult zooids are replaced by a new generation of buds. While this dynamic asexual development is a hallmark of the species, its molecular regulation remains poorly understood. This study presents the first comprehensive proteomic analysis ofB. schlosseriblastogenesis at the individual zooid level, using data-independent acquisition mass spectrometry to quantify protein abundance across developmental stages. The results reveal extensive proteome remodeling between proliferating buds and degenerating zooids. Co-expression analysis identified stage-specific protein modules enriched for biosynthesis and cell cycle pathways in buds, and for apoptosis, catabolism, and metabolic remodeling in zooids. A focused comparison between takeover buds and takeover zooids uncovered distinct regulatory programs controlling proliferation and senescence. Key proteins, including CDK1, CDK2, HDAC2, and PCNA, were identified as candidate regulators of cell cycle progression. These findings provide a molecular framework for understanding regeneration in a basal chordate and offer protein targets that may enable cell cycle re-entry and long-term culture of tunicate primary cells. Summary StatementThis study maps proteome dynamics during the blastogenic cycle inBotryllus schlosseri, identifying candidate proteins that regulate cell proliferation and offer targets for tunicate cell line development.
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- Award ID(s):
- 2127516
- PAR ID:
- 10613219
- Publisher / Repository:
- bioRxiv
- Date Published:
- Format(s):
- Medium: X
- Institution:
- bioRxiv
- Sponsoring Org:
- National Science Foundation
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Abstract This study establishes the copper tolerance range of the colonial marine tunicateBotryllus schlosseri. Furthermore, quantitative organismal phenotyping and quantitative proteomics were combined to characterize theB. schlosseriresponse to, and recovery from, acute copper exposure stress. Changes in the area ofB. schlossericolony systems and pigmentation provided sensitive, dose-dependent markers of exposure to, and recovery from, copper stress. Comprehensive quantitative proteomics using consistent data-independent acquisition (DIA) assay libraries revealed activation of detoxification, oxidative stress, and immune pathways during exposure to copper stress. In addition, quantitative proteomics uncovered enrichment of tissue remodeling and proliferative signaling pathways during recovery from copper stress. We identified 35 proteins whose expression closely mirrored phenotypic changes observed at the colonial system level. This specific proteome signature represents a comprehensive molecular underpinning of the organismal response ofB. schlosserito copper stress. In conclusion, this study establishes copper tolerance ranges of the invasive colonial tunicateB. schlosseriand explains the molecular underpinnings of stress-induced organismal phenotypes by identifying corresponding proteome signatures and their associated functional enrichments. Moreover, identification of copper concentrations that are stressful and highly disruptive on the molecular phenotype, yet readily recoverable from, lays a critical foundation for future studies directed at stress-induced adaptation and evolutionary trajectories of marine invertebrates in changing and novel environments.more » « less
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This study establishes the copper tolerance range of the colonial marine tunicate Botryllus schlosseri. Furthermore, quantitative organismal phenotyping and quantitative proteomics were combined to characterize the B. schlosseri response to, and recovery from, acute copper exposure stress. Changes in the area of B. schlosseri colony systems and pigmentation provided sensitive, dose-dependent markers of exposure to, and recovery from, copper stress. Comprehensive quantitative proteomics using consistent data-independent acquisition (DIA) assay libraries revealed activation of detoxification, oxidative stress, and immune pathways during exposure to copper stress. In addition, quantitative proteomics uncovered enrichment of tissue remodeling and proliferative signaling pathways during recovery from copper stress. We identified 35 proteins whose expression closely mirrored phenotypic changes observed at the colonial system level. This specific proteome signature represents a comprehensive molecular underpinning of the organismal response of B. schlosseri to copper stress. In conclusion, this study establishes copper tolerance ranges of the invasive colonial tunicate B. schlosseri and explains the molecular underpinnings of stress-induced organismal phenotypes by identifying corresponding proteome signatures and their associated functional enrichments. Moreover, identification of copper concentrations that are stressful and highly disruptive on the molecular phenotype, yet readily recoverable from, lays a critical foundation for future studies directed at stress-induced adaptation and evolutionary trajectories of marine invertebrates in changing and novel environments.more » « less
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- Posted Content:
- https://doi.org/10.1101/2025.07.01.662660
