Articles tagués limb

Zebrafish limb development is triggered by a retinoic acid signal during gastrulation

Zebrafish limb development is triggered by a retinoic acid signal during gastrulation

Heiner Grandel, Michael Brand

Developmental Dynamics Volume 240, Issue 5, pages 1116–1126, May 2011 doi: 10.1002/dvdy.22461

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The origins of the Drosophila leg revealed by the cis-regulatory architecture of the Distalless gene

The origins of the Drosophila leg revealed by the cis-regulatory architecture of the Distalless gene

Daniel J. McKay, Carlos Estella and Richard S. Mann

Development 136, 61-71 (2009) doi: doi: 10.1242/dev.02997510.1242/dev.029975

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Shared developmental mechanisms pattern the vertebrate gill arch and paired fin skeletons

Shared developmental mechanisms pattern the vertebrate gill arch and paired fin skeletons

J. Andrew Gillis, Randall D. Dahn, and Neil H. Shubin

PNAS Published online before print March 24, 2009, doi: 10.1073/pnas.0810959106


Ce faisant, d’un coup d’un seul, les
vertébrés sont apparus, avec tous leus attributs. [source]

D’un coup d’un seul hein ? 8)


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Tri-phasic expression of posterior Hox genes during development of pectoral fins in zebrafish: Implications for the evolution of vertebrate paired appendages

Tri-phasic expression of posterior Hox genes during development of pectoral fins in zebrafish: Implications for the evolution of vertebrate paired appendages

Ahn D, Ho RK

Dev Biol (2008 ) Article in press

« D’un coup d’un seul » hein ?

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Regulatory constraints in the evolution of the tetrapod limb anterior–posterior polarity

Regulatory constraints in the evolution of the tetrapod limb anterior–posterior polarity

Basile Tarchini, Denis Duboule and Marie Kmita

Nature 443, 985-988 (26 October 2006) | doi:10.1038/nature05247

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Visualization of Cartilage Formation: Insight into Cellular Properties of Skeletal Progenitors and Chondrodysplasia Syndromes

Visualization of Cartilage Formation: Insight into Cellular Properties of Skeletal Progenitors and Chondrodysplasia Syndromes

Visualization of Cartilage Formation: Insight into Cellular Properties of Skeletal Progenitors and Chondrodysplasia Syndromes

Maria Barna and Lee Niswander

Developmental Cell, Volume 12, Issue 6, 5 June 2007, Pages 931-941

The cellular events underlying skeletal morphogenesis and the formation of cartilage templates are largely unknown. We generated an imaging system to dynamically visualize limb mesenchymal cells undergoing successive phases in cartilage formation and to delineate the cellular function of key regulators of chondrogenesis found mutated in chondrodysplasia syndromes. We uncovered an unsuspected role for Sox9 in control of cell morphology, independent from its major downstream target ColIIa, critically required for the mesenchyme-to-chondrocyte transition. In contrast, Bmp signaling regulates a cellular program we term “compaction” in which mesenchymal cells acquire a cohesive cell behavior required to delineate the boundaries and size of cartilage elements. Moreover, we visualized labeled progenitor cells from different regions of the limb bud and identified unique cellular properties that may direct their contribution toward specific skeletal elements such as the humerus or digits. These findings shed light on the cellular basis for chondrodysplasia syndromes and formation of the vertebrate skeleton.

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Genetic evidence that FGFs have an instructive role in limb proximal–distal patterning

Genetic evidence that FGFs have an instructive role in limb proximal–distal patterning

Francesca V. Mariani, Christina P. Ahn & Gail R. Martin
These authors contributed equally to this work.

Nature 453, 401-405 (15 May 2008) | doi:10.1038/nature06876

Half a century ago, the apical ectodermal ridge (AER) at the distal tip of the tetrapod limb bud was shown to produce signals necessary for development along the proximal–distal (P–D) axis, but how these signals influence limb patterning is still much debated. Fibroblast growth factor (FGF) gene family members are key AER-derived signals, with Fgf4, Fgf8, Fgf9 and Fgf17 expressed specifically in the mouse AER. Here we demonstrate that mouse limbs lacking Fgf4, Fgf9 and Fgf17 have normal skeletal pattern, indicating that Fgf8 is sufficient among AER-FGFs to sustain normal limb formation. Inactivation of Fgf8 alone causes a mild skeletal phenotype; however, when we also removed different combinations of the other AER-FGF genes, we obtained unexpected skeletal phenotypes of increasing severity, reflecting the contribution that each FGF can make to the total AER-FGF signal. Analysis of the compound mutant limb buds revealed that, in addition to sustaining cell survival, AER-FGFs regulate P–D-patterning gene expression during early limb bud development, providing genetic evidence that AER-FGFs function to specify a distal domain and challenging the long-standing hypothesis that AER-FGF signalling is permissive rather than instructive for limb patterning. We discuss how a two-signal model for P–D patterning can be integrated with the concept of early specification to explain the genetic data presented here.

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Mice Given Bat-like Forelimbs

Molecular Evolution: Mice Given Bat-like Forelimbs Through Gene Switch A research team led by Dr. Richard Behringer at MD Anderson Cancer Center reports that they have successfully switched the mouse Prx1 gene regulatory element with the Prx1 gene regulatory region from a bat — and although these two species are separated by millions of years of evolution — the resulting transgenic mice displayed abnormally long forelimbs.

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