TY - JOUR
T1 - Regional requirements for Dishevelled signalling during Xenopus gastrulation
T2 - Separable effects on blastopore closure, mesendoderm internalization and archenteron formation
AU - Ewald, Andrew J.
AU - Peyrot, Sara M.
AU - Tyszka, Michael J.
AU - Fraser, Scott E.
AU - Wallingford, John B.
PY - 2004/12
Y1 - 2004/12
N2 - During amphibian gastrulation, the embryo is transformed by the combined actions of several different tissues. Paradoxically, many of these morphogenetic processes can occur autonomously in tissue explants, yet the tissues in intact embryos must interact and be coordinated with one another in order to accomplish the major goals of gastrulation: closure of the blastopore to bring the endoderm and mesoderm fully inside the ectoderm, and generation of the archenteron. Here, we present high-resolution 3D digital datasets of frog gastrulae, and morphometrics that allow simultaneous assessment of the progress of convergent extension, blastopore closure and archenteron formation in a single embryo. To examine how the diverse morphogenetic engines work together to accomplish gastrulation, we combined these tools with time-lapse analysis of gastrulation, and examined both wild-type embryos and embryos in which gastrulation was disrupted by the manipulation of Dishevelled (Xdsh) signaling. Remarkably, although inhibition of Xdsh signaling disrupted both convergent extension and blastopore closure, mesendoderm internalization proceeded very effectively in these embryos. In addition, much of archenteron elongation was found to be independent of Xdsh signaling, especially during the second half of gastrulation. Finally, even in normal embryos, we found a surprising degree of dissociability between the various morphogenetic processes that occur during gastrulation. Together, these data highlight the central role of PCP signaling in governing distinct events of Xenopus gastrulation, and suggest that the loose relationship between morphogenetic processes may have facilitated the evolution of the wide variety of gastrulation mechanisms seen in different amphibian species.
AB - During amphibian gastrulation, the embryo is transformed by the combined actions of several different tissues. Paradoxically, many of these morphogenetic processes can occur autonomously in tissue explants, yet the tissues in intact embryos must interact and be coordinated with one another in order to accomplish the major goals of gastrulation: closure of the blastopore to bring the endoderm and mesoderm fully inside the ectoderm, and generation of the archenteron. Here, we present high-resolution 3D digital datasets of frog gastrulae, and morphometrics that allow simultaneous assessment of the progress of convergent extension, blastopore closure and archenteron formation in a single embryo. To examine how the diverse morphogenetic engines work together to accomplish gastrulation, we combined these tools with time-lapse analysis of gastrulation, and examined both wild-type embryos and embryos in which gastrulation was disrupted by the manipulation of Dishevelled (Xdsh) signaling. Remarkably, although inhibition of Xdsh signaling disrupted both convergent extension and blastopore closure, mesendoderm internalization proceeded very effectively in these embryos. In addition, much of archenteron elongation was found to be independent of Xdsh signaling, especially during the second half of gastrulation. Finally, even in normal embryos, we found a surprising degree of dissociability between the various morphogenetic processes that occur during gastrulation. Together, these data highlight the central role of PCP signaling in governing distinct events of Xenopus gastrulation, and suggest that the loose relationship between morphogenetic processes may have facilitated the evolution of the wide variety of gastrulation mechanisms seen in different amphibian species.
KW - Dishevelled
KW - Gastrulation
KW - Morphogenesis
KW - Xenopus
UR - http://www.scopus.com/inward/record.url?scp=12344287455&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=12344287455&partnerID=8YFLogxK
U2 - 10.1242/dev.01542
DO - 10.1242/dev.01542
M3 - Article
C2 - 15548584
AN - SCOPUS:12344287455
SN - 0950-1991
VL - 131
SP - 6195
EP - 6209
JO - Development
JF - Development
IS - 24
ER -