BACKGROUND Morphogen gradients are thought to create concentration thresholds that differentially position the expression boundaries of multiple target genes. Despite intensive study, it is still unclear how the concentration profiles within gradients are spatially related to the critical patterning thresholds they generate. RESULTS Here we use a combination of quantitative measurements and e...

Recent in vivo experiments have illustrated the importance of understanding the haemodynamics of heart morphogenesis. In particular, ventricular trabeculation is governed by a delicate interaction between haemodynamic forces, myocardial activity, and morphogen gradients, all of which are coupled to genetic regulatory networks. The underlying haemodynamics at the stage of development in which th...

Hormetic morphogens are morphogens such as transforming growth factor beta (TGF-β) in mammals and auxin in plants that induce hormetic responses. For example, in vitro, TGF-β stimulates and inhibits cell proliferation at low and high concentrations respectively. I developed a model of hormetic morphogen gradient control of the morphogenesis of the fusion of bilateral aortic precursors (Anlagen)...

Recent advances in generating human organoids from embryoid bodies (EBs) of induced pluripotent stem cells (iPSCs) provide a promising tool for modeling organ development and disease. A major limitation current developed petri-dishes is that the EBs are surrounded symmetrically on all sides by growth factors extracellular matrix (ECM), leading to uncontrolled spontaneous organization tissue. Th...

Quasi-stable gradients of signaling protein molecules (known as morphogens or ligands) bound to cell receptors are known to be responsible for differential cell signaling and gene expressions. From these follow different stable cell fates and visually patterned tissues in biological development. Recent studies have shown that the relevant basic biological processes yield gradients that are sens...

Dachsous-Fat signaling via the Hippo pathway influences proliferation during Drosophila development, and some of its mammalian homologs are tumor suppressors, highlighting its role as a universal growth regulator. The Fat/Hippo pathway responds to morphogen gradients and influences the in-plane polarization of cells and orientation of divisions, linking growth with tissue patterning. Remarkably...

Source regions for morphogen gradients-organizing regions-can be generated if a local self-enhancing reaction is coupled with a long-ranging reaction that acts antagonistically. Resulting gradients can be translated into patterns of stable gene activities using genes whose products have a positive feedback on the activation on themselves. If several autoregulatory genes compete with each other ...

Epithelial tissues develop planar polarity that is reflected in the global alignment of hairs and cilia with respect to the tissue axes. The planar cell polarity (PCP) proteins form asymmetric and polarized domains across epithelial junctions that are aligned locally between cells and orient these external structures. Although feedback mechanisms can polarize PCP proteins intracellularly and lo...

BACKGROUND Gradients of morphogens pattern cell fate - a phenomenon that is especially important during development. A simple model system for studying how morphogens pattern cell behavior would overcome difficulties inherent in the study of natural morphogens in vivo. A synthetic biology approach to building such a system is attractive. RESULTS Using an externally-tunable band-pass filter pa...

How morphogen gradients are shaped is a major question in developmental biology, but remains poorly understood. Hedgehog (Hh) is a locally secreted ligand that reaches cells at a distance and acts as a morphogen to pattern the Drosophila wing and the vertebrate neural tube. The proper patterning of both structures relies on the precise control over the slope of Hh activity gradient. A number of...