Publications by authors named "A Chessel"
In the highly regulative embryo of the sea urchin Paracentrotus lividus, establishment of the dorsal-ventral (D/V) axis critically depends on the zygotic expression of the TGF-β nodal in the ventral ectoderm. nodal expression is first induced ubiquitously in the 32-cell embryo and becomes progressively restricted to the presumptive ventral ectoderm by the early blastula stage. This early spatial restriction of nodal expression is independent of Lefty, and instead relies on the activity of Panda, a maternally expressed TGF-β ligand related to Lefty and Inhibins, which is required maternally for D/V axis specification.
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- Calcific uremic arteriolopathy (CUA) is a serious condition mainly affecting patients with end-stage renal disease (ESRD) on dialysis, marked by calcium deposits in the skin.
- A study compared the elastic fiber structure and skin calcifications in 14 ESRD patients with CUA to 12 without using advanced imaging techniques.
- The findings revealed significant differences in elastic fiber fragmentation and the presence of massive circumferential vascular calcifications in CUA patients, suggesting these features might indicate a more specific link to CUA compared to general calcifications seen in other ESRD patients.
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- The human cornea maintains its curvature and refraction by adapting to changes in intraocular pressure, which involves a complex multiscale structure of collagen lamellae within the corneal stroma.
- This study employs second harmonic generation (SHG) microscopy to visualize collagen distribution across the full depth of ten intact human corneas, achieving high-resolution imaging while preserving the corneal shape.
- The findings reveal that collagen lamellae are primarily oriented along specific axes in the anterior and posterior stroma, with increased disorder in the anterior region, marking the first detailed characterization of corneal lamellar structure throughout its thickness.
During early development of the sea urchin embryo, activation of ERK signalling in mesodermal precursors is not triggered by extracellular RTK ligands but by a cell-autonomous, RAS-independent mechanism that was not understood. We discovered that in these cells, ERK signalling is activated through the transcriptional activation of a gene encoding a protein related to Kinase Suppressor of Ras, that we named KSR3. KSR3 belongs to a family of catalytically inactive allosteric activators of RAF.
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- Sea urchins serve as important models in developmental biology, and researchers created a detailed genome assembly to investigate their unique genetic traits compared to other deuterostomes.
- The study revealed that sea urchins maintain ancestral chromosome linkages but experience rapid shuffling of gene order, alongside a significant increase in gene duplication in their lineage.
- Key discoveries include the evolution of new structures from these duplicated genes and the conservation of certain gene-regulatory modules between sea urchins and chordates, indicating a shared developmental framework despite significant genomic changes.