scholarly journals Initiation of convergence and extension movements of lateral mesoderm during zebrafish gastrulation

2005 ◽  
Vol 234 (2) ◽  
pp. 279-292 ◽  
Author(s):  
Diane S. Sepich ◽  
Colette Calmelet ◽  
Maria Kiskowski ◽  
Lila Solnica-Krezel
Keyword(s):  
Convergence And Extension ◽  
Lateral Mesoderm

Pattern of the insulin-like growth factor II gene expression during early mouse embryogenesis

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 151-159 ◽  
Author(s):  
J.E. Lee ◽  
J. Pintar ◽  
A. Efstratiadis
Keyword(s):  
Growth Factor ◽  
Immunohistochemical Analysis ◽  
Primitive Streak ◽  
Insulin Like Growth Factor ◽  
Surface Ectoderm ◽  
Factor Ii ◽  
Extraembryonic Mesoderm ◽  
Early Mouse ◽  
Lateral Mesoderm

The mouse insulin-like growth factor II (IGF-II) gene encodes a polypeptide that plays a role in embryonic growth. We have examined the temporal and spatial pattern of expression of this gene in sections of the mouse conceptus between embryonic days 4.0 and 8.5 by in situ hybridization. Abundant IGF-II transcripts were detected in all the trophectodermal derivatives, after implantation. Labeling was then observed in primitive endoderm, but was transient and disappeared after formation of the yolk sac. Expression was next detected in extraembryonic mesoderm at the early primitive streak stage. Labeling in the embryo proper appeared first at the late primitive streak/neural plate stage in lateral mesoderm and in anterior-proximal cells located between the visceral endoderm and the most cranial region of the embryonic ectoderm. The position of the latter cells suggests that their descendants are likely to participate in the formation of the heart and the epithelium of the ventral and lateral walls of the foregut, where intense labeling was observed at the neural fold stage. Hybridization was also detected in cranial mesenchyme, including neural crest cells. The intensity of hybridization signal increased progressively in paraxial (presomitic and somitic) mesoderm, while declining in the ectoplacental cone. The neuroectoderm and surface ectoderm did not exhibit hybridization at any stage. Immunohistochemical analysis indicated co-localization of IGF-II transcripts, translated pre-pro-IGF-II, and the cognate IGF-II/mannose-6-phosphate receptor. These correlations are consistent with the hypothesis that IGF-II has an autocrine function.

scholarly journals Setdb2 controls convergence and extension movements during zebrafish gastrulation by transcriptional regulation of dvr1

2014 ◽  
Vol 392 (2) ◽  
pp. 233-244 ◽  
Author(s):  
Ting-Ting Du ◽  
Peng-Fei Xu ◽  
Zhi-Wei Dong ◽  
Hong-Bo Fan ◽  
Yi Jin ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Convergence And Extension

scholarly journals Unipolar distributions of junctional Myosin II identify cell stripe boundaries that drive cell intercalation throughout Drosophila axis extension

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Robert J Tetley ◽  
Guy B Blanchard ◽  
Alexander G Fletcher ◽  
Richard J Adams ◽  
Bénédicte Sanson
Keyword(s):  
Myosin Ii ◽  
Interaction Model ◽  
Cell Interaction ◽  
Cell Number ◽  
Cell Polarization ◽  
Convergence And Extension ◽  
Pair Rule Gene ◽  
Cell Intercalation ◽  
Pair Rule ◽  
Cell Cell

Convergence and extension movements elongate tissues during development. Drosophila germ-band extension (GBE) is one example, which requires active cell rearrangements driven by Myosin II planar polarisation. Here, we develop novel computational methods to analyse the spatiotemporal dynamics of Myosin II during GBE, at the scale of the tissue. We show that initial Myosin II bipolar cell polarization gives way to unipolar enrichment at parasegmental boundaries and two further boundaries within each parasegment, concomitant with a doubling of cell number as the tissue elongates. These boundaries are the primary sites of cell intercalation, behaving as mechanical barriers and providing a mechanism for how cells remain ordered during GBE. Enrichment at parasegment boundaries during GBE is independent of Wingless signaling, suggesting pair-rule gene control. Our results are consistent with recent work showing that a combinatorial code of Toll-like receptors downstream of pair-rule genes contributes to Myosin II polarization via local cell-cell interactions. We propose an updated cell-cell interaction model for Myosin II polarization that we tested in a vertex-based simulation.

The somatic-visceral subdivision of the embryonic mesoderm is initiated by dorsal gradient thresholds in Drosophila

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 2107-2116 ◽  
Author(s):  
K. Maggert ◽  
M. Levine ◽  
M. Frasch
Keyword(s):  
Expression Pattern ◽  
Target Genes ◽  
Substantial Reduction ◽  
Drosophila Embryo ◽  
Germ Layers ◽  
Cardiac Tissues ◽  
Early Drosophila Embryo ◽  
Dorsal Ectoderm ◽  
Lateral Mesoderm

The maternal dorsal regulatory gradient initiates the differentiation of the mesoderm, neuroectoderm and dorsal ectoderm in the early Drosophila embryo. Two primary dorsal target genes, snail (sna) and decapentaplegic (dpp), define the limits of the presumptive mesoderm and dorsal ectoderm, respectively. Normally, the sna expression pattern encompasses 18–20 cells in ventral and ventrolateral regions. Here we show that narrowing the sna pattern results in fewer invaginated cells. As a result, the mesoderm fails to extend into lateral regions so that fewer cells come into contact with dpp-expressing regions of the dorsal ectoderm. This leads to a substantial reduction in visceral and cardiac tissues, consistent with recent studies suggesting that dpp induces lateral mesoderm. These results also suggest that the dorsal regulatory gradient defines the limits of inductive interactions between germ layers after gastrulation. We discuss the parallels between the subdivision of the mesoderm and dorsal ectoderm.

FGF signalling in the early specification of mesoderm in Xenopus

Development ◽  
1993 ◽  
Vol 118 (2) ◽  
pp. 477-487 ◽  
Author(s):  
E. Amaya ◽  
P.A. Stein ◽  
T.J. Musci ◽  
M.W. Kirschner
Keyword(s):  
Dorsal Side ◽  
Dominant Negative ◽  
Early Gene ◽  
Immediate Early ◽  
Mesoderm Induction ◽  
Fgf Receptor ◽  
Muscle Formation ◽  
Fgf Signalling ◽  
Lateral Mesoderm

We have examined the role of FGF signalling in the development of muscle and notochord and in the expression of early mesodermal markers in Xenopus embryos. Disruption of the FGF signalling pathway by expression of a dominant negative construct of the FGF receptor (XFD) generally results in gastrulation defects that are later evident in the formation of the trunk and tail, though head structures are formed nearly normally. These defects are reflected in the loss of notochord and muscle. Even in embryos that show mild defects and gastrulate properly, muscle formation is impaired, suggesting that morphogenesis and tissue differentiation each depend on FGF. The XFD protein inhibits the expression of the immediate early gene brachyury throughout the marginal zone, including the dorsal side; it does not, however, inhibit the dorsal lip marker goosecoid, which is expressed in the first involuting mesoderm at the dorsal side that will underlie the head. The XFD protein also inhibits Xpo expression, an immediate early marker of ventral and lateral mesoderm. These results suggest that FGF is involved in the earliest events of most mesoderm induction that occur before gastrulation and that the early dorsal mesoderm is already composed of two cell populations that differ in their requirements for FGF.

An atlas of notochord and somite morphogenesis in several anuran and urodelean amphibians

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 223-247
Author(s):  
B. Woo Youn ◽  
R. E. Keller ◽  
G. M. Malacinski
Keyword(s):  
Posterior Part ◽  
Ambystoma Mexicanum ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Scanning Electron Microscopic ◽  
Somite Formation ◽  
Comparative Survey ◽  
Pleurodeles Waltlii ◽  
Lateral Mesoderm ◽  
Somitic Mesoderm

A scanning electron microscopic, comparative survey of notochord and somite formation including some details of change in cell morphology and arrangement, was made of selected stages of two species of anuran amphibians (Xenopus laevis and Rana pipiens) and two species of urodeles (Ambystoma mexicanum and Pleurodeles waltlii). The ectoderm or neural plate was removed from fixed embryos and the dorsal aspect of the developing notochord and somite mesoderm was photographed. Micrographs of comparable stages of all species were arranged together to form an atlas of notochord and somite formation. Similar morphogenetic events occur in the same sequence in the four species. Notochordal cells become distinguishable from paraxial mesodermal cells by shape, closeness of packing, and arrangement. Notochordal elongation is accompanied by a decrease in cross-sectional area and by cell rearrangement. Somitic mesoderm becomes distinguished from lateral mesoderm by a change in cell shape and orientation, followed by segmentation of somites. The schedule of somite formation was compared and related to the staging series for each species. The urodeles differ from the anurans in that the notochordal region in the early neurula stages is triangular, with the broadest part in the posterior region of the embryo. In anurans it is uniform in width. This difference may reflect differences in gastrulation and in the mechanism of elongation of the posterior part of the embryo in the neurula.

Expression of the LIM class homeobox gene Xlim-1 in pronephros and CNS cell lineages of Xenopus embryos is affected by retinoic acid and exogastrulation

Development ◽  
1994 ◽  
Vol 120 (6) ◽  
pp. 1525-1536 ◽  
Author(s):  
M. Taira ◽  
H. Otani ◽  
M. Jamrich ◽  
I.B. Dawid
Keyword(s):  
Retinoic Acid ◽  
Organizer Region ◽  
Homeobox Gene ◽  
Second Phase ◽  
Cell Specification ◽  
Spemann Organizer ◽  
Xenopus Embryos ◽  
Prechordal Mesoderm ◽  
The Central Nervous System ◽  
Lateral Mesoderm

The LIM class homeobox gene Xlim-1 is expressed in Xenopus embryos in the lineages leading to (i) the notochord, (ii) the pronephros, and (iii) certain cells of the central nervous system (CNS). In its first expression phase, Xlim-1 mRNA arises in the Spemann organizer region, accumulates in prechordal mesoderm and notochord during gastrulation, and decays in these tissues during neurula stages except that it persists in the posterior tip of the notochord. In the second phase, expression in lateral mesoderm begins at late gastrula, and converges to the pronephros at tailbud stages. Expression in a central location of the neural plate also initiates at late gastrula, expands anteriorly and posteriorly, and becomes established in the lateral regions of the spinal cord and hindbrain at tailbud stages. Thus Xlim-1 expression precedes morphogenesis, suggesting that it may be involved in cell specification in these lineages. Enhancement of Xlim-1 expression by retinoic acid (RA) was first detectable in the dorsal mesoderm at initial gastrula. During gastrulation and early neurulation, RA strongly enhanced Xlim-1 expression in all three lineages and also expanded its expressing domains; this overexpression correlated well with RA phenotypes such as enlarged pronephros and hindbrain-like structure. Exogastrulation reduced Xlim-1 expression in the lateral mesoderm and ectoderm but not in the notochord, suggesting that the second phase of Xlim-1 expression requires mesoderm/ectoderm interactions. RA treatment of exogastrulae did not revert this reduction.

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