Biology subjects

Zilliox, M.

Publications and source records attributed to Zilliox, M..

4 recordsLinked to original sources

bioRxiv2026

LipoTag: A minimal motif for live and functional imaging of plant cell membranes.

The plant plasma membrane is a highly dynamic structure that is crucial for cell compartmentalization, the maintenance of (bio)chemical gradients, signaling and cell growth and responses to stress. In plants, plasma membranes are tightly connected to the cell walls that encase them. These cell walls can act as diffusion barriers and prevent the use of a wide range of synthetic fluorescent probes that have been developed to study animal cell membranes, which lack a cell wall, with live functional imaging. Here, we introduce LipoTag, a minimal chemical motif that, upon chemical conjugation, transforms hydrophobic fluorophores into water-soluble, membrane-targeted probes that can permeate plant cell walls to reach their intended location. LipoTag uses a localized positive charge in combination with a short aliphatic spacer to direct cargo to the plasma membrane. We used LipoTag to develop a suite of membrane-specific fluorescent probes that work in walled organisms beyond the plant kingdom. In addition, we used LipoTag to develop functional reporters for the quantitative imaging of membrane density, lipid order and membrane oxidation in living plant tissues. LipoTag forms a modular platform for exploring the plant plasma membrane with a suite of contemporary imaging modalities.

plant biology↗

bioRxiv2025

SBIS, a new orange fluorescent vital probe for the 4D imaging of brown algal cells

Living cells of brown algae are difficult to observe in 3D because pigments such as fucoxanthin and chlorophyll diffract light. Furthermore, at the beginning of their life, brown algae develop slowly in seawater. To gain insight into the 3D shape and size of brown algal cells during embryogenesis, we designed a fluorescence probe that efficiently and selectively labels the plasma membrane. Styryl benzoindoleninium sulfonate (SBIS) is a bright orange fluorogenic probe that is soluble and virtually non-emissive in seawater and is activated upon binding to the plasma membrane. Unlike Calcofluor White, SBIS enables observation of cells at thicknesses of up to 25 {micro}m. More importantly, SBIS allows three-dimensional observation of the cells in the growing uniseriate filaments of Ectocarpus sp., the polystichous filaments of Sphacelaria rigidula and the cellular monolayered lamina of Saccharina latissima over periods of up to seven days. Altogether, these properties allow visualization of the entire cell contours in living brown algae, making the study of early development at the cellular level in 4D now possible in these marine organisms.

cell biology↗

bioRxiv2024

Local activation of Cxcl12a signaling controls olfactory placode morphogenesis in zebrafish embryos

Morphogenesis and cell-type differentiation are highly coordinated in sensory organs to ensure their function. Morphogenesis of the olfactory epithelium (OE) in zebrafish provides a unique model to study this process as undifferentiated cells aligned around the anterior neural plate mature into clusters of early olfactory neurons across a short time scale. While the Cxcl12a/Cxcr4b signaling pathway drives this process, what constraints on pathway activation apply during morphogenesis are unclear. We developed a mathematical model recapitulating Cxcl12a-mediated OE morphogenesis. Restoring Cxcl12a expression in mutants for the ligand rescues correct morphogenesis both in silico and in vivo. However, where expression of the ligand is restored is crucial for rescue, a point not predicted by our model and suggesting an unexpected level of pathway activation control. Analysis of a Cxcr4b activation reporter supports this idea. We concluded that mosaic and heterochronic Cxcl12a activation along the anteroposterior axis sculpts the olfactory epithelium.

developmental biology↗

bioRxiv2024

A toolkit for testing membrane localisation tags across species

Transgenic markers and tools have revolutionised how we study cells and developing organisms. Some of the elements needed to construct those tools are universally applicable (e.g. fluorescent proteins), while others are species-specific (e.g. cis-regulatory elements driving transcription). Membrane-localising signals that target proteins to the plasma membrane have been identified in several model organisms. Unfortunately, the efficacy of these signals varies greatly across species. To address this problem, we generated a toolkit of 11 membrane-localising tags that can be screened rapidly in diverse organisms. The toolkit includes tags that target the plasma membrane through different mechanisms, including signal peptides, the attachment of lipids, and fusion with lipid-binding domains. Each tag has been fused to the red fluorescent protein mScarlet3 and placed downstream of a T7 promoter, allowing the in vitro production of mRNA that can be readily delivered in a wide range of embryos and cells of interest. Through a collaborative effort, we tested this toolkit in ten species of animals spanning diverse phyla, including chordates, echinoderms, arthropods, nematodes, annelids, flatworms and cnidarians. We identify robust membrane-localising tags in each of these animals, and in one of animals closest relatives, the choanoflagellates. Three tags (KRas, GAP43 and Src64B) work in all of the species tested.

developmental biology↗