Biology subjects

Hoogenberg, B.

Publications and source records attributed to Hoogenberg, B..

3 recordsLinked to original sources

bioRxiv2026

Concanavalin A as a pan-eukaryotic nuclear envelope marker for expansion microscopy

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.

cell biology↗

bioRxiv2025

Temporal and spatial coordination of DNA segregation and cell division in an archaeon.

Cells must coordinate DNA segregation with cytokinesis to ensure that each daughter cell inherits a complete genome. Here, we explore how DNA segregation and division are mechanistically coupled in archaeal relatives of eukaryotes, which lack CDK/Cyclins. Using live cell imaging we first describe the series of sequential changes in DNA organisation that accompany cell division in Sulfolobus, which computational modelling shows likely aid genome segregation. Through a perturbation analysis we identify a regulatory checkpoint which ensures that the compaction of the genome into two spatially segregated nucleoids only occurs once cells have assembly a division ring - which also defines the axis of DNA segregation. Finally, we show that DNA compaction and segregation depends, in part, on a ParA homologue, SegA, and its partner SegB, whose absence leads to bridging DNA. Taken together, these data show how regulatory checkpoints like those operating in eukaryotes aid high-fidelity division in an archaeon.

cell biology↗

bioRxiv2022

Nuclear poly-glutamine aggregates rupture the nuclear envelope and hinder its repair

Huntingtons disease (HD) is caused by a poly-glutamine expansion of the huntingtin protein, resulting in the formation of poly-glutamine aggregates. The mechanisms of toxicity that result in the complex HD pathology remain only partially understood. Here we show that nuclear polyglutamine aggregates deform the nuclear envelope (NE) and induce NE ruptures that are often repaired incompletely. These ruptures coincide with deformations of the nuclear lamina and lead to lamina scar formation. Expansion microscopy enabled resolving the ultrastructure of nuclear aggregates and revealed polyglutamine fibrils sticking into the cytosol at rupture sites, suggesting a mechanism for incomplete repair. These findings implicate nuclear polyQ aggregate-induced loss of NE integrity as a potential contributing factor to Huntingtons disease and other polyglutamine diseases. One-sentence summaryAggregates associated with Huntingtons Disease induce ruptures of the nuclear envelop that compromise its barrier function

cell biology↗