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The Cnidarian and the Canon: the role of Wnt/β‐catenin signaling in the evolution of metazoan embryos
Author(s) -
Primus Alex,
Freeman Gary
Publication year - 2004
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.20031
Subject(s) - gastrulation , wnt signaling pathway , mesoderm , biology , blastomere , endoderm , embryo , microbiology and biotechnology , germ layer , polarity (international relations) , polarity in embryogenesis , frizzled , evolutionary biology , genetics , embryonic stem cell , signal transduction , embryogenesis , cell , gene , induced pluripotent stem cell
In a recent publication, Wikramanayake and colleagues have implicated the canonical Wnt/β‐catenin signaling pathway as a mediator of axial polarity and germ‐layer specification in embryos of the cnidarian Nematostella .1 In this anthozoan, β‐catenin is localized in nuclei of blastomeres in one region of the 16‐ to 32‐cell embryo whose descendants subsequently form the entoderm of the embryo. They claim that the pattern of nuclear localization is significant for two reasons: (1) when nuclear localization of β‐catenin was inhibited, gastrulation does not occur, and (2) when localization of β‐catenin took place in all cells of the pregastrula embryo, the number of entodermal cells increases. Since the Wnt/β‐catenin signaling pathway also plays a role in establishing axial polarity and specifying endoderm and mesoderm in a number of bilaterians,2–6 Wikramanayake et al. imply that this developmental mechanism is an evolutionary inheritance from a radially symmetrical ancestor. Some of the gaps in the current evidence, which must be filled to evaluate their interpretation, are discussed. BioEssays 26:474–478, 2004. © 2004 Wiley Periodicals, Inc.