Biology subjects

Lecaudey, V.

Publications and source records attributed to Lecaudey, V..

8 recordsLinked to original sources

bioRxiv2026

Shroom3-dependent pillar cell constriction establishes a mechanical threshold for respiratory lamellar stability

How developing organs acquire complex architectures while maintaining tissue integrity under mechanical stress is a fundamental question in mechanobiology. In the gill, pillar cells support the thin respiratory lamellae, but how they withstand hemodynamic forces is unknown. Here, we show that actomyosin-rich contractile apparatuses (CA) in zebrafish pillar cells act as load-bearing units that generate contractile forces and stabilize the lamellae through adhesion to and enclosure of extracellular collagen columns. CA number correlates with pillar cell constriction, linking subcellular architecture to tissue geometry. We further identify Shroom3 and Vinculin b as key regulators of CA assembly and force transmission: shroom3 deficiency or loss of vclb impairs CA formation and reduces pillar cell constriction, while loss of shroom3 causes lamellar collapse. Together, these findings support a mechanical threshold model in which lamellar integrity depends on a minimum number of CAs per pillar cell and establish the gill lamellae as a model for linking subcellular contractility to tissue-scale mechanical stability.

developmental biology↗

bioRxiv2025

Patterned integrin-laminin adhesion coordinates epithelial collective cell migration

Collective cell migration is essential for development, tissue homeostasis, and disease progression. Although integrin-mediated adhesion is well characterized in single migrating cells in vitro, how integrins coordinate collective epithelial migration in vivo is less clear. Using the zebrafish posterior lateral line primordium (pLLP), we show that integrins 3 and 6 are differentially expressed in the trailing and leading regions of the pLLP, respectively, and that their combined loss induces excessive protrusive activity and slows migration. We further identify laminin 5 (Lama5) as a key basement membrane (BM) component underlying migrating pLLP cells. While loss of laminin 5 alone compromises BM integrity without impairing migration, simultaneous depletion of lama5 and itga6b markedly decreases velocity, and ultimately blocks migration. These findings reveal a robust, redundant adhesion machinery that ensures persistent collective migration in vivo and highlight fundamental principles of epithelial dynamics relevant to development and disease.

developmental biology↗

bioRxiv2025

Lifelong development of zebrafish gills: Asymmetries in early vascular patterning predict adult gill architecture

Gills are essential for fish respiration and have a highly specialized cellular architecture enabling efficient gas exchange. Surprisingly, the developmental processes underlying gill formation in zebrafish remain poorly understood. Here, we present for the first time a comprehensive analysis of the morphogenesis of gill arteries, filaments and lamellae during lifelong development. Our results provide important insights into the temporal and spatial pattern of gill angiogenesis, revealing fundamental differences in the formation of lateral versus medial filaments along the dorso-ventral axis. These early asymmetries correlate with, and likely underlie, the structural asymmetries observed in adult gills, which we quantitatively characterize. This indicates that a region-specific developmental programme establishes a blueprint for gill architecture maintained throughout life. We further show that lamellae develop through a complex interplay between endothelial and cranial neural crest-derived pillar cells. Notably, lamellar size, which strongly influences respiratory efficiency, depends on the position of the filament in the arch. Together, our work identifies key cellular and temporal mechanisms driving gill development and provides a framework to investigate broader principles of branching morphogenesis and angiogenesis in vertebrates.

developmental biology↗

bioRxiv2025

Vgll4 Proteins limit Organ Size in Zebrafish through Yap1-Dependent and -Independent Mechanisms

Precise control of organ size is crucial during development and homeostasis. Dysregulation of the underlying mechanisms can result in organ malformation and tumorigenesis. Although the Hippo signaling pathway plays a key role in regulating organ growth, the precise regulation of its effectors, YAP1 and WWTR1, remains unclear. To gain insights into tissue growth control during organ formation, we used the zebrafish posterior lateral line primordium (pLLP), a migratory group of epithelial cells that forms sensory organs, as a model. We demonstrate that Yap1 growth-promoting activity in the pLL system is modulated not only in the cytoplasm but also in the nucleus by Vgll4 proteins. We propose a model in which Yap1, together with Tead proteins, ensures that the pLLP contains a sufficient number of cells before migration begins. Vgll4b and Vgll4l, in contrast, function partially redundantly, to limit pLLP cell number, with Vgll4b showing a stronger tumor-suppressor activity. Our data indicate that Vgll4b/4l counteract Yap1 activity by competing with Yap1 for binding to Tead proteins, but also via a Yap1-independent mechanism. Altogether, this study reveals that a precise balance between Yap1 and Vgll4 proteins ensures proper regulation of cell number in the pLLP.

developmental biology↗

bioRxiv2019

Intraflagellar transport complex B proteins regulate the Hippo effector Yap1 during cardiogenesis

Cilia and the intraflagellar transport (IFT) proteins involved in ciliogenesis are associated with congenital heart diseases (CHD). However, the molecular links between cilia, IFT proteins and cardiogenesis are yet to be established. Using a combination of biochemistry, genetics, and live imaging methods, we show that IFT complex B proteins (Ift88, Ift54 and Ift20) modulate the Hippo pathway effector YAP1 in zebrafish and mouse. We demonstrate that this interaction is key to restrict the formation of the proepicardium and the myocardium. In cellulo experiments suggest that IFT88 and IFT20 interact with YAP1 in the cytoplasm and functionally modulates its activity, identifying a molecular link between cilia related proteins and the Hippo pathway. Taken together, our results highlight a novel role for IFT complex B proteins during cardiogenesis and shed light on an unexpected mechanism of action for ciliary proteins in YAP1 regulation. These findings provide mechanistic insights into a non-canonical role for cilia related proteins during cardiogenesis.

developmental biology↗

bioRxiv2019

Morphogenesis is transcriptionally coupled to neurogenesis during olfactory placode development

Sense organs acquire their distinctive shapes concomitantly with the differentiation of sensory cells and neurons necessary for their function. While our understanding of the mechanisms controlling morphogenesis and neurogenesis in these structures has grown, how these processes are coordinated remains largely unexplored. Neurogenesis in the zebrafish olfactory epithelium requires the bHLH proneural transcription factor Neurogenin1 (Neurog1). To address whether Neurog1 also controls morphogenesis in this system, we analysed the morphogenetic behaviour of early olfactory neural progenitors in neurog1 mutant embryos. Our results indicate that the oriented movements of these progenitors are disrupted in this context. Morphogenesis is similarly affected by mutations in the chemokine receptor gene, cxcr4b, suggesting it is a potential Neurog1 target gene. We find that Neurog1 directly regulates cxcr4b through an E-boxes cluster located just upstream of the cxcr4b transcription start site. Our results suggest that proneural transcription factors, such as Neurog1, directly couple distinct aspects of nervous system development. One Sentence SummaryNeurog1 controls olfactory organ morphogenesis via cxcr4b

developmental biology↗

bioRxiv2018

YAP/TAZ-TEAD Activity Links Mechanical Cues To Specific Cell Fate Within The Hindbrain Boundaries

Cells perceive their microenvironment through chemical and physical cues. However, how mechanical signals are interpreted during embryonic tissue deformation resulting in specific cell behaviors is largely unexplored. The Yap/Taz family of transcriptional co-activators has emerged as an important regulator of tissue growth and regeneration, responding to physical cues from the extracellular matrix, cell shape and actomyosin cytoskeleton. In this work, we unveiled the role of Yap/Taz-TEAD activity as sensor of mechanical signals in the regulation of the progenitor behavior of boundary cells during hindbrain compartmentalization. Monitoring in vivo Yap/Taz-activity during hindbrain segmentation we discovered that boundary cells respond to mechanical cues in a cell-autonomous manner through Yap/Taz-TEAD activity. Cell-lineage analysis revealed that Yap/Taz-TEAD boundary cells decrease their proliferative activity when Yap/Taz-TEAD ceased, preceding changes of cell fate: from proliferating progenitors to differentiated neurons. Functional experiments demonstrated the pivotal role of Yap/Taz-TEAD signaling in maintaining the progenitor features in the hindbrain boundary cell population.

developmental biology↗

bioRxiv2018

The Hippo pathway effector Taz is required for cell fate specification and fertilization in zebrafish

In the last decade, Hippo signaling has emerged as a critical pathway integrating extrinsic and intrinsic mechanical cues to regulate cell proliferation and survival, tissue morphology and organ size in vivo. Despite its essential role in organogenesis, surprisingly much less is known about how it connects biomechanical signals to control of cell fate and cell size during development. Here we unravel a novel and unexpected role of the Hippo pathway effector Taz (wwtr1) in the control of cell size and cell fate specification. In teleosts, fertilization occurs through a specific structure at the animal pole, called the micropyle. This opening in the chorion is formed during oogenesis by a specialized somatic follicle cell, the micropylar cell (MC). The MC has a peculiar shape and is much larger than its neighboring follicle cells but the mechanisms underlying its specification and cell shape acquisition are not known. Here we show that Taz is essential for the specification of the MC and subsequent micropyle formation in zebrafish. We identify Taz as the first bona fide MC marker and show that Taz is specifically and strongly enriched in the MC precursor before the cell can be identified morphologically. Altogether, our genetic data and molecular characterization of the MC lead us to propose that Taz is a key regulator of the MC fate activated by physical cues emanating from the oocyte to initiate the MC morphogenetic program. We describe here for the first time the mechanism underlying the specification of the MC fate.

developmental biology↗