Biology subjects

Curantz, C.

Publications and source records attributed to Curantz, C..

6 recordsLinked to original sources

bioRxiv2025

Cross-Species Biomechanical Determinants of Shape Diversity

How complex molecular mechanisms translate into diverse multicellular shapes remains unclear. By leveraging the bi-layered architecture of six cnidarian species that diverged 500 million years ago, we show that modularity in supracellular mechanics governs larval shape diversity. Using active surface theory, quantitative imaging, and an inducible genetic system, we identify species-specific variations in three biomechanical modules. Basally aligned stress fibers drive axial elongation, while oral geometry and aboral rigidity define shape polarity. Remarkably, manipulating these modules transforms one species shape into another, demonstrating the causal relationship between module variation and shape diversity. Our analysis also uncovers instances of mechanical redundancies, where distinct module combinations generate similar shapes. These findings provide a general framework for how molecular complexity funnels into mesoscale mechanical determinants shaping morphological diversity.

developmental biology↗

bioRxiv2025

An unexpected mode of whole-body regeneration from reaggregated cell suspension in Hydractinia (Cnidaria, Hydrozoa)

Hydrozoan cnidarians are among the few animals that can regenerate whole bodies from reaggregated cell dissociations but the cellular and molecular mechanisms that control this ability and how it is related to embryonic development are not well understood. Furthermore, the evolution of this type of regeneration is enigmatic since it does not occur naturally. Here, we show that aggregate regeneration in Hydractinia symbiolongicarpus proceeds through several, consistent stages that include the formation of an epidermal layer, followed by migration, proliferation, and differentiation of adult pluripotent stem cells, known as i-cells. Migration of i-cells is controlled by sphingosine-1-phosphate signaling. Single-cell transcriptomics revealed, surprisingly, that the newly regenerated individual derives nearly exclusively from i-cell progeny rather than from recycled somatic cells, as seen in other hydrozoans. Given the similarity of this phenomenon to embryogenesis, we propose that the ability of Hydractinia cell aggregates to regenerate is a side effect of the animals i-cell-mediated development.

developmental biology↗

bioRxiv2024

A positive feedback loop between germ cells and gonads induces and maintains cnidarian sexual reproduction

The fertile gonad includes cells of two distinct developmental origins: the somatic mesoderm and the germline. How somatic and germ cells interact to develop and maintain fertility is not well understood. Here, using grafting experiments and transgenic reporter animals, we find that a specific part of the gonad-the germinal zone-acts as a sexual organizer to induce and maintain de novo germ cells and somatic gonads in non-sexual tissue in the cnidarian Hydractinia symbiolongicarpus. We further show that germ cells express a novel member of the TGF-{beta} family (Gonadless, Gls) that induces somatic gonad morphogenesis. Loss of Gls resulted in animals lacking somatic gonadal structures but having few, non-proliferative germ cells. We propose a model according to which a small number of primary germ cells drive gonad development though Gls morphogen secretion. The germinal zone in the newly formed gonad, in turn, provides positive feedback to induce secondary germ cells by activating Tfap2 (the master regulator of germ cell fate) in resident pluripotent stem cells. De novo induction of germ cells by gonads in adult life is absent in bilaterians with a sequestered germline. However, the contribution of germ cell signaling to the patterning of somatic gonadal tissue, as observed in Hydractinia, may be a general animal feature.

developmental biology↗

bioRxiv2021

A conserved paint box underlies color pattern diversity in Estrildid finches

Many animals exhibit typical color patterns that have been linked to key adaptive functions, yet the developmental mechanisms establishing these crucial designs remain unclear. Here, we surveyed color distribution in the plumage across a large number of passerine finches. Despite extreme apparent pattern diversity, we identified a small set of conserved color regions whose combinatory association can explain all observed patterns. We found these domains are instructed by early embryonic landmarks, and through profiling and comparative analyses produced a molecular map marking putative color domains in the developing skin. This revealed cryptic pre-patterning common to differently colored species, uncovering a simple molecular landscape underlying extensive color pattern variation.

developmental biology↗

bioRxiv2021

Cell shape anisotropy and motility constrain self-organised feather pattern fidelity in birds

Cellular self-organisation can emerge from stochastic fluctuations in properties of a developing tissue1-3. This mechanism explains the production of various motifs seen in nature4-7. However, events channelling its outcomes such that patterns are produced with reproducible precision key to fitness remain unexplored. Here, we compared the dynamic emergence of feather primordia arrays in poultry, finch, emu, ostrich and penguin embryos and correlated inter-species differences in pattern fidelity to the amplitude of dermal cell anisotropy in the un-patterned tissue. Using live imaging and ex vivo perturbations in these species, we showed that cell anisotropy optimises cell motility for sharp and precisely located primordia formation, and thus, proper pattern geometry. These results evidence a mechanism through which collective cellular properties of a developmental pattern system ensure stability in its self-organisation and contribute to its evolution.

developmental biology↗

bioRxiv2018

Symmetry breaking in the embryonic skin triggers a directional and sequential front of competence during plumage patterning

The development of an organism involves the formation of patterns from initially homogeneous surfaces in a reproducible manner. Simulations of various theoretical models recapitulate final states of natural patterns1-4 yet drawing testable hypotheses from those often remains difficult4,5. Consequently, little is known on pattern-forming events. Here, we extend modeling to reproduce not only the final plumage pattern of birds, but also the observed natural variation in its dynamics of emergence in five species. We built a unified model intrinsically generating the directionality, sequence, and duration of patterning, and used in vivo experiments to test its parameter-based predictions. We showed that while patterning duration is controlled by overall cell proliferation, its directional and sequential progression result from a pre-pattern: an initial break in surface symmetry launches a traveling front of increased cell density that defines domains with self-organizing capacity. These results show that universal mechanisms combining pre-patterning and self-organization govern the timely emergence of the plumage pattern in birds.

developmental biology↗