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Symmetry breakage in the frog Xenopus : Role of Rab11 and the ventral‐right blastomere
Author(s) -
Tingler Melanie,
Ott Tim,
Tözser Janos,
Kurz Sabrina,
Getwan Maike,
Tisler Matthias,
Schweickert Axel,
Blum Martin
Publication year - 2014
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/dvg.22766
Subject(s) - nodal signaling , biology , gastrulation , xenopus , nodal , neurulation , microbiology and biotechnology , lateral plate mesoderm , zebrafish , anatomy , blastomere , cilium , mesoderm , fate mapping , embryo , genetics , embryogenesis , progenitor cell , embryonic stem cell , stem cell , gene
Summary Vertebrates display asymmetric arrangements of inner organs such as heart and stomach. The Nodal signaling cascade in the left lateral plate mesoderm in all cases directs asymmetric morphogenesis and placement during organogenesis. Mechanisms that lead up to left‐asymmetric Nodal induction seem to differ between the vertebrates. Cilia produce a leftward extracellular fluid flow in zebrafish, medaka, mouse, rabbit, and Xenopus embryos during neurulation. In Xenopus , earlier asymmetric cues were described. Some, such as Rab11, apparently act in the zygote. Others were efficiently manipulated in ventral‐right cells at the four‐cell stage, a lineage presumably independent of the ciliated gastrocoel roof plate (GRP) during neurulation. Here, we show that one‐ and four‐cell manipulations of Rab11 showed equal low efficiencies of left–right disturbances. We also reevaluated the lineage of the GRP. By tracing back future ciliated cells from the gastrula to the four‐cell stage, we show that ventral cells contribute to ciliated sensory cells at the border of the GRP. Knockdown of the Nodal inhibitor Coco in the ventral right lineage resulted in embryos with ectopic right‐sided Nodal and Pitx2c expression. Together, these experiments support a cilia‐based mechanism of symmetry breakage in the frog Xenopus . genesis 52:588–599, 2014. © 2014 Wiley Periodicals, Inc.