Biology subjects

Schuetz, L.

Publications and source records attributed to Schuetz, L..

4 recordsLinked to original sources

bioRxiv2025

Mechanics and growth coordination define SOSEKI-based polarity fields

The formation of organs requires the coordinated growth of cells and tissues relative to the main body axes. Plant growth is typically anisotropic and mechanically coupled through contiguous cell walls, yet how these physical patterns link to cell and tissue polarity remains unclear. Here, we use SOSEKI (SOK) proteins--previously thought to report global polarity fields--as markers to dissect how polarity arises during lateral root (LR) organogenesis. Live imaging revealed that SOK polarisation does not follow a uniform global field but instead responds to local differences in growth and mechanical state between neighbouring tissues. SOKs accumulate at interfaces separating domains of distinct growth behaviour and dissipate under compressive stress. After perturbing tissue interfaces or the mechanical continuity of the tissue, the coherence of the polarity was disrupted, indicating that stable axis establishment requires mechanical coupling across the cell wall network. Our results suggest that SOK polarisation is mechanoresponsive, linking tissue mechanics to polarity and axis establishment.

plant biology↗

bioRxiv2025

A network of RS splicing regulatory proteins controls light-dependent splicing and seedling development

The light-induced change from skoto- to photomorphogenesis is a key switch in plant development that requires global transcriptome reprogramming. Earlier studies in Arabidopsis thaliana and other plant species have revealed the eminent role of alternative precursor mRNA splicing (AS), which allows fine-tuning the expression of numerous genes including light signaling and photosynthesis-related components in response to the ambient light conditions. Starting from the previous finding that AS changes induced by either light or metabolic signals are linked to phospho-signaling, we applied phospho-proteomics to identify proteins that undergo rapid changes in their phosphorylation status upon exposing etiolated seedlings to either light or sucrose. This approach revealed hyperphosphorylation of RS41, a member of the RS subfamily of serine/arginine-rich (SR) proteins. To study the function of the four RS genes RS31, RS31a, RS40, and RS41, a comprehensive set of single and higher order mutants was generated. A complete loss of RS function in the quadruple mutant caused sterility. Moreover, the important role of the RS proteins in seedling photomorphogenesis was demonstrated, with both redundant and specific functions in the regulation of hypocotyl elongation and cotyledon opening. We further identified the critical contribution of the RS proteins to light-dependent alternative splicing, being part of an intricate network of splicing regulatory components. Our study provides novel insight into the complex network of RNA-binding proteins that allow balancing light-responsive splicing and development in Arabidopsis seedlings.

plant biology↗

bioRxiv2020

Integration of Cell Growth and Asymmetric Division During Lateral Root Initiation In Arabidopsis thaliana

Lateral root formation determines to a large extent the ability of plants to forage their environment and thus their growth. In Arabidopsis thaliana and other angiosperms, lateral root initiation requires radial cell expansion and several rounds of anticlinal cell divisions that give rise to a central core of small pericycle cells, which express different markers than the larger surrounding cells. These small central cells then switch their plane of divisions to periclinal, and give rise to seemingly morphologically similar daughter cells that have different identities and establish the different cell types of the new root. Although the execution of these two types of divisions is tightly regulated and essential for the correct development of the lateral root, we know little about their geometrical features. Here we analyse a four-dimensional reconstruction of the first stages of lateral root formation and analyze the geometric features of the anticlinal and periclinal divisions. We identify that the periclinal divisions of the small central cells are morphologically dissimilar and asymmetric. We show that mother cell volume is different when looking at anticlinal versus periclinal divisions and the repeated anticlinal divisions do not lead to reduction in cell volume although cells are shorter. Finally, we show that cells undergoing a periclinal division are characterized by a strong cell expansion. Our results indicate that cells integrate growth and division to precisely partition their volume upon division during the first two stages of lateral root formation.

plant biology↗

bioRxiv2017

Optic Fissure Margin Morphogenesis Sets The Stage For Consecutive Optic Fissure Fusion, Pioneered By A Distinct Subset Of Margin Cells Using A Hyaloid Vessel As Scaffold

The optic fissure is a transient gap in the developing optic cup of vertebrates. Persisting optic fissures, coloboma, are a frequent reason for blindness in children. Although many genes have been linked to coloboma, it has remained unclear how the two bi-layered epithelia comprising the optic fissure margins are fusing to form a continuous neuroretina and retinal pigmented epithelium (RPE) respectively. Besides, highly variable morphologies of coloboma phenotypes strongly argue for a diverse set of underlying pathomechanisms.\n\nHere we investigated the contribution of the individual cell types with 4D in vivo time-lapse analyses using zebrafish (Danio rerio). This allowed defining the respective roles of the participating tissues and cell populations and their activities during fissure morphogenesis, contact formation between the margins as well as during fusion.\n\nWe show that optic fissure closure is initiated by a bilateral tissue flow partially in continuation of the dynamic optic cup morphogenesis but additionally including a tissue flow from the optic stalk. This process is followed by the setup of specific fissure margins by a distinct cell population translocating from of the optic stalk. The morphological fusion is triggered by in an EMT-like disassembly of the fissure margin driven by bi-potential pioneer cells that ultimately take the fate of both, neuroretina and RPE respectively. The consecutive fusion and re-epithelialization transforms the two initially separated epithelial bilayers into the two continuous layers of neuroretina and RPE. The processes described here in detail represents a fundamental mechanism of the seamless connection of adjacent multilayered epithelia and is highly reminiscent of other fusion processes, like palatal shelf fusion with key relevance for development and growth.

developmental biology↗