Publications
A Geometric Model of Stripe Refinement
Organizing data about patterning and morphogenesis into a coherent framework remains a challenge in developmental biology. Reporting in Science, Corson et al. (2017) apply innovative analysis to an old problem of bristle patterns in Drosophila, reducing the nonlinear interactions among tens of cells to a succinct model with quantitative predictions. © 2017 Elsevier Inc.
Long-Term High-Resolution Imaging of Developing C. elegans Larvae with Microfluidics
Long-term studies of Caenorhabditis elegans larval development traditionally require tedious manual observations because larvae must move to develop, and existing immobilization techniques either perturb development or are unsuited for young larvae. Here, we present a simple microfluidic device to simultaneously follow development of ten C. elegans larvae at high spatiotemporal resolution from hatching to adulthood (∼3 days).
A Balance between Secreted Inhibitors and Edge Sensing Controls Gastruloid Self-Organization
The earliest aspects of human embryogenesis remain mysterious. To model patterning events in the human embryo, we used colonies of human embryonic stem cells (hESCs) grown on micropatterned substrate and differentiated with BMP4. These gastruloids recapitulate the embryonic arrangement of the mammalian germ layers and provide an assay to assess the structural and signaling mechanisms patterning the human gastrula.
Self-organization of human embryonic stem cells on micropatterns
Fate allocation in the gastrulating embryo is spatially organized as cells differentiate into specialized cell types depending on their positions with respect to the body axes. There is a need for in vitro protocols that allow the study of spatial organization associated with this developmental transition. Although embryoid bodies and organoids can exhibit some spatial organization of differentiated cells, methods that generate embryoid bodies or organoids do not yield consistent and fully reproducible results.
Small-scale anisotropy in turbulent boundary layers
In a channel flow, the velocity fluctuations are inhomogeneous and anisotropic. Yet, the small-scale properties of the flow are expected to behave in an isotropic manner in the very-large-Reynolds-number limit. We consider the statistical properties of small-scale velocity fluctuations in a turbulent channel flow at moderately high Reynolds number , using the Johns Hopkins University Turbulence Database.
Predicting Ancestral Segmentation Phenotypes from Drosophila to Anopheles Using In Silico Evolution
Molecular evolution is an established technique for inferring gene homology but regulatory DNA turns over so rapidly that inference of ancestral networks is often impossible. In silico evolution is used to compute the most parsimonious path in regulatory space for anterior-posterior patterning linking two Dipterian species. The expression pattern of gap genes has evolved between Drosophila (fly) and Anopheles (mosquito), yet one of their targets, eve, has remained invariant.
Self-organization of the in vitro attached human embryo
Implantation of the blastocyst is a developmental milestone in mammalian embryonic development. At this time, a coordinated program of lineage diversification, cell-fate specification, and morphogenetic movements establishes the generation of extra-embryonic tissues and the embryo proper, and determines the conditions for successful pregnancy and gastrulation. Despite its basic and clinical importance, this process remains mysterious in humans. Here we report the use of a novel in vitro system to study the post-implantation development of the human embryo.
Temperature compensation and temperature sensation in the circadian clock
All known circadian clocks have an endogenous period that is remarkably insensitive to temperature, a property known as temperature compensation, while at the same time being readily entrained by a diurnal temperature oscillation. Although temperature compensation and entrainment are defining features of circadian clocks, their mechanisms remain poorly understood.
Comment on "controlling long-term signaling: Receptor dynamics determine attenuation and refractory behavior of the TGF-b pathway"-Smad2/3 activity does not predict the dynamics of transcription
The transforming growth factor-b (TGF-b) pathway plays a fundamental role in development and disease. Despite its importance, the dynamics of signaling activity downstream of ligand stimulation have remained largely unexplored. The recent study by Vizán et al. demonstrates that loss of signaling-capable receptors from the cell surface leads to a refractory period during which cells are incapable of responding to additional signals.
A method to recapitulate early embryonic spatial patterning in human embryonic stem cells
Embryos allocate cells to the three germ layers in a spatially ordered sequence. human embryonic stem cells (hescs) can generate the three germ layers in culture; however, differentiation is typically heterogeneous and spatially disordered. We show that geometric confnement is suffcient to trigger self-organized patterning in hescs. in response to BmP4, colonies reproducibly differentiated to an outer trophectoderm-like ring, an inner ectodermal circle and a ring of mesendoderm expressing primitive-streak markers in between.