Year: 2026
Type: preprint
Abstract: Across eukaryotes, the nuclear envelope exhibits distinct remodelling strategies during mitosis: complete breakdown (open mitosis), partial disruption (intermediate), or full retention (closed). However, both light and electron microscopy of the nuclear envelope, at sufficient resolution to determine integrity and mode of remodelling, have proven technically challenging. Here, Concanavalin A (ConA), a glycan-binding plant lectin, provides discernible nuclear envelope/endoplasmic reticulum (NE/ER) labelling in Ultrastructure Expansion Microscopy (U-ExM). Applied post-expansion, ConA circumvents antibody optimisation and labels the NE across mammalian cells and diverse microbial eukaryotes. By imaging four opisthokont and amoebozoan species with established mitotic strategies, C. perkinsii, D. discoideum, S. pombe , and S. arctica , we distinguished the full spectrum of NE remodelling. Applied to species with poorly characterised mitotic strategies, ConA revealed intermediate mitosis with polar fenestrae in the multinucleate stramenopile A. limacinum and a life cycle-coupled switch between open and closed mitosis in the amoebozoan P. polycephalum . These observations support the hypothesis that multinucleated life cycles favour closed or intermediate mitosis, protecting chromosomes from capture by neighbouring spindles during synchronous divisions. Together, these results establish ConA in combination with expansion microscopy as a broadly applicable tool for uncovering the diversity and evolution of NE remodelling across eukaryotes.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funders: National Science Foundation, Gordon and Betty Moore Foundation, University of Bern, Queen Mary University of London, Mylan, European Commission, École Polytechnique Fédérale de Lausanne, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Akademie Věd České Republiky, Centre National de la Recherche Scientifique, Université de Genève, School of Medicine, Indiana University
OpenAlex ID: W7212121301