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Two‐dimensional morphogen gradient in Xenopus : Boundary formation and real‐time transduction response
Author(s) -
Kinoshita T.,
Jullien J.,
Gurdon J.B.
Publication year - 2006
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20963
Subject(s) - morphogen , xenopus , biology , embryo , microbiology and biotechnology , gastrulation , concentration gradient , endoderm , biophysics , anatomy , embryogenesis , genetics , cellular differentiation , chemistry , gene , environmental chemistry
Morphogen gradients play an important role in pattern formation in embryo. However, the interpretation of position in a morphogen gradient is not well understood. Because it is hard to analyze morphogen gradients especially in opaque embryos such as those of Xenopus , it is necessary to fix and section the embryo, thereby eliminating the possibility of real‐time observation, and making more difficult the interpretation of events that take place in three dimensions. We describe here a two‐dimensional preparation of cells from a Xenopus blastula animal cap, in which an activin concentration gradient appears to be formed and interpreted at the same rate and in the same way as in normal embryos. We use two‐dimensional preparations of this kind to contribute the following new information about gradient formation and interpretation in embryo. We determine the dynamics of formation of an activin activity gradient in real time. We demonstrate that this gradient is established by diffusion of activin through intercellular space and does not require internalization of receptor or ligand. We also show that the generation of a boundary of gene expression depends on the interpretation, rather than a change of composition, of the concentration gradient. Developmental Dynamics 235:3189–3198, 2006. © 2006 Wiley‐Liss, Inc.