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Most bilaterians exhibit a left-right asymmetric distribution of their internal organs. The sea urchin larva is notable in this regard since most adult structures are generated from left sided embryonic structures. The gene regulatory network governing this larval asymmetry is still a work in progress but involves several conserved signaling pathways including Nodal, and BMP. Here we provide a comprehensive analysis of Hedgehog signaling and it''s contribution to left-right asymmetry. We report that Hh signaling plays a conserved role to regulate late asymmetric expression of Nodal and that this regulation occurs after Nodal breaks left-right symmetry in the mesoderm. Thus, while Hh functions to maintain late Nodal expression, the molecular asymmetry of the future coelomic pouches is locked in. Furthermore we report that cilia play a role only insofar as to transduce Hh signaling and do not have an independent effect on the asymmetry of the mesoderm. From this, we are able to construct a more complete regulatory network governing the establishment of left-right asymmetry in the sea urchin.
Angerer,
Animal-vegetal axis patterning mechanisms in the early sea urchin embryo.
2000, Pubmed,
Echinobase
Angerer,
Animal-vegetal axis patterning mechanisms in the early sea urchin embryo.
2000,
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
Blum,
Symmetry breakage in the vertebrate embryo: when does it happen and how does it work?
2014,
Pubmed
Cameron,
The oral-aboral axis of a sea urchin embryo is specified by first cleavage.
1989,
Pubmed
,
Echinobase
Campanale,
Migration of sea urchin primordial germ cells.
2014,
Pubmed
,
Echinobase
Dathe,
Morphological left-right asymmetry of Hensen's node precedes the asymmetric expression of Shh and Fgf8 in the chick embryo.
2002,
Pubmed
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 signaling organizes the oral-aboral axis of the sea urchin embryo.
2004,
Pubmed
,
Echinobase
Lapraz,
RTK and TGF-beta signaling pathways genes in the sea urchin genome.
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
Levin,
A molecular pathway determining left-right asymmetry in chick embryogenesis.
1995,
Pubmed
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
Materna,
Notch and Nodal control forkhead factor expression in the specification of multipotent progenitors in sea urchin.
2013,
Pubmed
,
Echinobase
McGrath,
Two populations of node monocilia initiate left-right asymmetry in the mouse.
2003,
Pubmed
Meyers,
Differences in left-right axis pathways in mouse and chick: functions of FGF8 and SHH.
1999,
Pubmed
Molina,
Nodal: master and commander of the dorsal-ventral and left-right axes in the sea urchin embryo.
2013,
Pubmed
,
Echinobase
Morris,
Heterotrimeric kinesin-II is required for the assembly of motile 9+2 ciliary axonemes on sea urchin embryos.
1997,
Pubmed
,
Echinobase
Pehrson,
The fate of the small micromeres in sea urchin development.
1986,
Pubmed
,
Echinobase
Range,
Cis-regulatory analysis of nodal and maternal control of dorsal-ventral axis formation by Univin, a TGF-beta related to Vg1.
2007,
Pubmed
,
Echinobase
Schilling,
Regulation of left-right asymmetries in the zebrafish by Shh and BMP4.
1999,
Pubmed
Stubbs,
The forkhead protein Foxj1 specifies node-like cilia in Xenopus and zebrafish embryos.
2008,
Pubmed
Su,
Telling left from right: left-right asymmetric controls in sea urchins.
2014,
Pubmed
,
Echinobase
Tanaka,
FGF-induced vesicular release of Sonic hedgehog and retinoic acid in leftward nodal flow is critical for left-right determination.
2005,
Pubmed
Tsiairis,
An Hh-dependent pathway in lateral plate mesoderm enables the generation of left/right asymmetry.
2009,
Pubmed
Vandenberg,
A unified model for left-right asymmetry? Comparison and synthesis of molecular models of embryonic laterality.
2013,
Pubmed
Walton,
Hedgehog signaling patterns mesoderm in the sea urchin.
2009,
Pubmed
,
Echinobase
Warner,
Hedgehog signaling requires motile cilia in the sea urchin.
2014,
Pubmed
,
Echinobase
Yajima,
Small micromeres contribute to the germline in the sea urchin.
2011,
Pubmed
,
Echinobase
Zhou,
Nodal is a novel TGF-beta-like gene expressed in the mouse node during gastrulation.
1993,
Pubmed