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Sea urchin embryos begin zygotic transcription shortly after the egg is fertilized. Throughout the cleavage stages a series of transcription factors are activated and, along with signaling through a number of pathways, at least 15 different cell types are specified by the beginning of gastrulation. Experimentally, perturbation of contributing transcription factors, signals and receptors and their molecular consequences enabled the assembly of an extensive gene regulatory network model. That effort, pioneered and led by Eric Davidson and his laboratory, with many additional insights provided by other laboratories, provided the sea urchin community with a valuable resource. Here we describe the approaches used to enable the assembly of an advanced gene regulatory network model describing molecular diversification during early development. We then provide examples to show how a relatively advanced authenticated network can be used as a tool for discovery of how diverse developmental mechanisms are controlled and work.
Figure 1. . Steps in construction and validation of developmental gene regulatory networks (dGRNs).The process begins with identification of candidate molecules. Candidates for the sea urchin dGRN were defined as transcription factors or signal transduction pathway members that were expressed in spatiotemporally specific patterns in the embryo. The regulatory linkages were established by conducting perturbation analyses in which one candidate was perturbed and asking how its loss affected expression of other candidates. These established a preliminary dGRN model. That model was challenged in many ways, including testing predictions that gene A activated gene B and gene C through cis-regulatory analysis.
Figure 2. . The patterning sequence of development results in cell diversification.Over the 24 hours from fertilization to the pluteus larval stage of
Lytechinus variagatus, the number of developmental gene regulatory network (dGRN) states increases until there are more than 15 cell types in the early larva.
Figure 3. . Process diagram of early development.Maternal inputs initiate specification. As cells divide, signaling becomes increasingly used to shape the specification sequence of each cell type. Toward the end of that process and proximal to differentiation, transcription factor sub-circuits drive expression of genes involved in differentiation and in morphogenesis.
Adomako-Ankomah,
Growth factor-mediated mesodermal cell guidance and skeletogenesis during sea urchin gastrulation.
2013, Pubmed,
Echinobase
Adomako-Ankomah,
Growth factor-mediated mesodermal cell guidance and skeletogenesis during sea urchin gastrulation.
2013,
Pubmed
,
Echinobase
Andrikou,
Logics and properties of a genetic regulatory program that drives embryonic muscle development in an echinoderm.
2015,
Pubmed
,
Echinobase
Armstrong,
Cell-cell interactions regulate skeleton formation in the sea urchin embryo.
1993,
Pubmed
,
Echinobase
Barsi,
Geometric control of ciliated band regulatory states in the sea urchin embryo.
2015,
Pubmed
,
Echinobase
Bessodes,
Reciprocal signaling between the ectoderm and a mesendodermal left-right organizer directs left-right determination in the sea urchin embryo.
2012,
Pubmed
,
Echinobase
Bolouri,
Modeling DNA sequence-based cis-regulatory gene networks.
2002,
Pubmed
,
Echinobase
Bradham,
Chordin is required for neural but not axial development in sea urchin embryos.
2009,
Pubmed
,
Echinobase
Bradham,
The sea urchin kinome: a first look.
2006,
Pubmed
,
Echinobase
Croce,
A genome-wide survey of the evolutionarily conserved Wnt pathways in the sea urchin Strongylocentrotus purpuratus.
2006,
Pubmed
,
Echinobase
Croce,
Wnt6 activates endoderm in the sea urchin gene regulatory network.
2011,
Pubmed
,
Echinobase
Cui,
Specific functions of the Wnt signaling system in gene regulatory networks throughout the early sea urchin embryo.
2014,
Pubmed
,
Echinobase
Davidson,
Properties of developmental gene regulatory networks.
2008,
Pubmed
,
Echinobase
Davidson,
Network design principles from the sea urchin embryo.
2009,
Pubmed
,
Echinobase
Davidson,
Gene regulatory networks and the evolution of animal body plans.
2006,
Pubmed
Davidson,
A genomic regulatory network for development.
2002,
Pubmed
,
Echinobase
Duboc,
Nodal and BMP2/4 signaling organizes the oral-aboral axis of the sea urchin embryo.
2004,
Pubmed
,
Echinobase
Duboc,
Left-right asymmetry in the sea urchin embryo is regulated by nodal signaling on the right side.
2005,
Pubmed
,
Echinobase
Duboc,
Lefty acts as an essential modulator of Nodal activity during sea urchin oral-aboral axis formation.
2008,
Pubmed
,
Echinobase
Duboc,
Nodal and BMP2/4 pattern the mesoderm and endoderm during development of the sea urchin embryo.
2010,
Pubmed
,
Echinobase
Duloquin,
Localized VEGF signaling from ectoderm to mesenchyme cells controls morphogenesis of the sea urchin embryo skeleton.
2007,
Pubmed
,
Echinobase
Erkenbrack,
Evolutionary rewiring of gene regulatory network linkages at divergence of the echinoid subclasses.
2015,
Pubmed
,
Echinobase
Ettensohn,
Lessons from a gene regulatory network: echinoderm skeletogenesis provides insights into evolution, plasticity and morphogenesis.
2009,
Pubmed
,
Echinobase
Ettensohn,
Encoding anatomy: developmental gene regulatory networks and morphogenesis.
2013,
Pubmed
,
Echinobase
Gao,
Juvenile skeletogenesis in anciently diverged sea urchin clades.
2015,
Pubmed
,
Echinobase
Haillot,
The Maternal Maverick/GDF15-like TGF-β Ligand Panda Directs Dorsal-Ventral Axis Formation by Restricting Nodal Expression in the Sea Urchin Embryo.
2015,
Pubmed
,
Echinobase
Hinman,
Caught in the evolutionary act: precise cis-regulatory basis of difference in the organization of gene networks of sea stars and sea urchins.
2007,
Pubmed
,
Echinobase
Hinman,
Developmental gene regulatory network architecture across 500 million years of echinoderm evolution.
2003,
Pubmed
,
Echinobase
Howard-Ashby,
Identification and characterization of homeobox transcription factor genes in Strongylocentrotus purpuratus, and their expression in embryonic development.
2006,
Pubmed
,
Echinobase
Howard-Ashby,
Gene families encoding transcription factors expressed in early development of Strongylocentrotus purpuratus.
2006,
Pubmed
,
Echinobase
Lapraz,
Patterning of the dorsal-ventral axis in echinoderms: insights into the evolution of the BMP-chordin signaling network.
2009,
Pubmed
,
Echinobase
Lapraz,
RTK and TGF-beta signaling pathways genes in the sea urchin genome.
2006,
Pubmed
,
Echinobase
Lapraz,
A deuterostome origin of the Spemann organiser suggested by Nodal and ADMPs functions in Echinoderms.
2015,
Pubmed
,
Echinobase
Li,
Encoding regulatory state boundaries in the pregastrular oral ectoderm of the sea urchin embryo.
2014,
Pubmed
,
Echinobase
Li,
New regulatory circuit controlling spatial and temporal gene expression in the sea urchin embryo oral ectoderm GRN.
2013,
Pubmed
,
Echinobase
Logan,
Nuclear beta-catenin is required to specify vegetal cell fates in the sea urchin embryo.
1999,
Pubmed
,
Echinobase
Longabaugh,
Visualization, documentation, analysis, and communication of large-scale gene regulatory networks.
2009,
Pubmed
Luo,
Opposing nodal and BMP signals regulate left-right asymmetry in the sea urchin larva.
2012,
Pubmed
,
Echinobase
Lyons,
Specification to biomineralization: following a single cell type as it constructs a skeleton.
2014,
Pubmed
,
Echinobase
Martik,
Deployment of a retinal determination gene network drives directed cell migration in the sea urchin embryo.
2015,
Pubmed
,
Echinobase
Materna,
The C2H2 zinc finger genes of Strongylocentrotus purpuratus and their expression in embryonic development.
2006,
Pubmed
,
Echinobase
Materna,
Notch and Nodal control forkhead factor expression in the specification of multipotent progenitors in sea urchin.
2013,
Pubmed
,
Echinobase
McCauley,
Development of an embryonic skeletogenic mesenchyme lineage in a sea cucumber reveals the trajectory of change for the evolution of novel structures in echinoderms.
2012,
Pubmed
,
Echinobase
McClay,
Evolutionary crossroads in developmental biology: sea urchins.
2011,
Pubmed
,
Echinobase
McIntyre,
Short-range Wnt5 signaling initiates specification of sea urchin posterior ectoderm.
2013,
Pubmed
,
Echinobase
McIntyre,
Branching out: origins of the sea urchin larval skeleton in development and evolution.
2014,
Pubmed
,
Echinobase
Oliveri,
Repression of mesodermal fate by foxa, a key endoderm regulator of the sea urchin embryo.
2006,
Pubmed
,
Echinobase
Oliveri,
Activation of pmar1 controls specification of micromeres in the sea urchin embryo.
2003,
Pubmed
,
Echinobase
Oliveri,
Global regulatory logic for specification of an embryonic cell lineage.
2008,
Pubmed
,
Echinobase
Peter,
The endoderm gene regulatory network in sea urchin embryos up to mid-blastula stage.
2010,
Pubmed
,
Echinobase
Peter,
A gene regulatory network controlling the embryonic specification of endoderm.
2011,
Pubmed
,
Echinobase
Piacentino,
Late Alk4/5/7 signaling is required for anterior skeletal patterning in sea urchin embryos.
2015,
Pubmed
,
Echinobase
Rafiq,
Genome-wide analysis of the skeletogenic gene regulatory network of sea urchins.
2014,
Pubmed
,
Echinobase
Range,
Integration of canonical and noncanonical Wnt signaling pathways patterns the neuroectoderm along the anterior-posterior axis of sea urchin embryos.
2013,
Pubmed
,
Echinobase
Röttinger,
FGF signals guide migration of mesenchymal cells, control skeletal morphogenesis [corrected] and regulate gastrulation during sea urchin development.
2008,
Pubmed
,
Echinobase
Saudemont,
Ancestral regulatory circuits governing ectoderm patterning downstream of Nodal and BMP2/4 revealed by gene regulatory network analysis in an echinoderm.
2010,
Pubmed
,
Echinobase
Saunders,
Sub-circuits of a gene regulatory network control a developmental epithelial-mesenchymal transition.
2014,
Pubmed
,
Echinobase
Sethi,
Sequential signaling crosstalk regulates endomesoderm segregation in sea urchin embryos.
2012,
Pubmed
,
Echinobase
Sethi,
Gene regulatory network interactions in sea urchin endomesoderm induction.
2009,
Pubmed
,
Echinobase
Sherwood,
Identification and localization of a sea urchin Notch homologue: insights into vegetal plate regionalization and Notch receptor regulation.
1997,
Pubmed
,
Echinobase
Sherwood,
LvNotch signaling mediates secondary mesenchyme specification in the sea urchin embryo.
1999,
Pubmed
,
Echinobase
Sodergren,
The genome of the sea urchin Strongylocentrotus purpuratus.
2006,
Pubmed
,
Echinobase
Su,
A perturbation model of the gene regulatory network for oral and aboral ectoderm specification in the sea urchin embryo.
2009,
Pubmed
,
Echinobase
Sweet,
LvDelta is a mesoderm-inducing signal in the sea urchin embryo and can endow blastomeres with organizer-like properties.
2002,
Pubmed
,
Echinobase
Walton,
Genomics and expression profiles of the Hedgehog and Notch signaling pathways in sea urchin development.
2006,
Pubmed
,
Echinobase
Walton,
Hedgehog signaling patterns mesoderm in the sea urchin.
2009,
Pubmed
,
Echinobase
Weitzel,
Differential stability of beta-catenin along the animal-vegetal axis of the sea urchin embryo mediated by dishevelled.
2004,
Pubmed
,
Echinobase
Wikramanayake,
beta-Catenin is essential for patterning the maternally specified animal-vegetal axis in the sea urchin embryo.
1998,
Pubmed
,
Echinobase
Wray,
The origin of spicule-forming cells in a 'primitive' sea urchin (Eucidaris tribuloides) which appears to lack primary mesenchyme cells.
1988,
Pubmed
,
Echinobase
Yankura,
Uncoupling of complex regulatory patterning during evolution of larval development in echinoderms.
2010,
Pubmed
,
Echinobase