scholarly journals Gene regulatory network subcircuit controlling a dynamic spatial pattern of signaling in the sea urchin embryo

2008 ◽  
Vol 105 (51) ◽  
pp. 20089-20094 ◽  
Author(s):  
J. Smith ◽  
E. H. Davidson
Keyword(s):  
Spatial Pattern ◽  
Gene Regulatory Network ◽  
Sea Urchin ◽  
Regulatory Network ◽  
Sea Urchin Embryo ◽  
Gene Regulatory

scholarly journals Encoding regulatory state boundaries in the pregastrular oral ectoderm of the sea urchin embryo

2014 ◽  
Vol 111 (10) ◽  
pp. E906-E913 ◽  
Author(s):  
Enhu Li ◽  
Miao Cui ◽  
Isabelle S. Peter ◽  
Eric H. Davidson
Keyword(s):  
Spatial Pattern ◽  
Sea Urchin ◽  
Regulatory Network ◽  
Regulatory State ◽  
Apical Plate ◽  
Sea Urchin Embryo ◽  
Oral Ectoderm ◽  
Positive Regulators ◽  
Gene Regulatory ◽  
Per Se

By gastrulation the ectodermal territories of the sea urchin embryo have developed an unexpectedly complex spatial pattern of sharply bounded regulatory states, organized orthogonally with respect to the animal/vegetal and oral/aboral axes of the embryo. Although much is known of the gene regulatory network (GRN) linkages that generate these regulatory states, the principles by which the boundaries between them are positioned and maintained have remained undiscovered. Here we determine the encoded genomic logic responsible for the boundaries of the oral aspect of the embryo that separate endoderm from ectoderm and ectoderm from neurogenic apical plate and that delineate the several further subdivisions into which the oral ectoderm per se is partitioned. Comprehensive regulatory state maps, including all spatially expressed oral ectoderm regulatory genes, were established. The circuitry at each boundary deploys specific repressors of regulatory states across the boundary, identified in this work, plus activation by broadly expressed positive regulators. These network linkages are integrated with previously established interactions on the oral/aboral axis to generate a GRN model encompassing the 2D organization of the regulatory state pattern in the pregastrular oral ectoderm of the embryo.

scholarly journals Early asymmetric cues triggering the dorsal/ventral gene regulatory network of the sea urchin embryo

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Vincenzo Cavalieri ◽  
Giovanni Spinelli
Keyword(s):  
Gene Regulatory Network ◽  
Sea Urchin ◽  
Regulatory Network ◽  
Ectopic Expression ◽  
Paracentrotus Lividus ◽  
Loss Of Function ◽  
Mapk Activity ◽  
Sea Urchin Embryo ◽  
Gene Regulatory ◽  
Dorsal Cells

Dorsal/ventral (DV) patterning of the sea urchin embryo relies on a ventrally-localized organizer expressing Nodal, a pivotal regulator of the DV gene regulatory network. However, the inceptive mechanisms imposing the symmetry-breaking are incompletely understood. In Paracentrotus lividus, the Hbox12 homeodomain-containing repressor is expressed by prospective dorsal cells, spatially facing and preceding the onset of nodal transcription. We report that Hbox12 misexpression provokes DV abnormalities, attenuating nodal and nodal-dependent transcription. Reciprocally, impairing hbox12 function disrupts DV polarity by allowing ectopic expression of nodal. Clonal loss-of-function, inflicted by blastomere transplantation or gene-transfer assays, highlights that DV polarization requires Hbox12 action in dorsal cells. Remarkably, the localized knock-down of nodal restores DV polarity of embryos lacking hbox12 function. Finally, we show that hbox12 is a dorsal-specific negative modulator of the p38-MAPK activity, which is required for nodal expression. Altogether, our results suggest that Hbox12 function is essential for proper positioning of the DV organizer.

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