File:Posterior forelimb bud identity.png

Establishment of posterior forelimb bud identity requires Hand2

(A,B) The loss of the posterior Tbx3 and Tbx2 expression domains in early Hand2 deficient (H2Δ/Δc) limb buds (from E9.75: 27 somites to E10.5: 35 somites) points to a failure in establishing posterior identity upstream of Shh activation. Open arrowheads: loss of expression in Hand2 deficient forelimb buds; solid arrowheads: normal expression in wild-type and Shh deficient limb buds. By E10.25–10.5 the posterior expression of Tbx2 and Tbx3 is also down-regulated in ShhΔ/Δ limb buds.

(C–E) Posterior expansion of anterior markers in H2Δ/Δc limb buds. (C) Crystallin-μ (Cry-μ) is expressed ectopically in the posterior mesenchyme of H2Δ/Δc limb buds at E10.0 (30 somites; indicated by solid arrowheads). The ectopic posterior Cry-μ expression is detected earlier than in Hand2 than Shh deficient limb buds (not shown). The Alx4 (D) and Gli3 (E) expression domains are posteriorly expanded (indicated by arrows) in Hand2 deficient limb buds at E9.75 (27 somites) and E10.25 (32 somites), respectively. Note that the posterior expansion of the Gli3 expression domain is less pronounced in ShhΔ/Δc than in H2Δ/Δc limb buds. In all panels, limb buds are oriented with the anterior to the top and the posterior to the bottom.

Reference

<pubmed>20386744</pubmed>| PLoS Genet.

Copyright

This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.

Citation: Galli A, Robay D, Osterwalder M, Bao X, Bénazet J-D, et al. (2010) Distinct Roles of Hand2 in Initiating Polarity and Posterior Shh Expression during the Onset of Mouse Limb Bud Development. PLoS Genet 6(4): e1000901. doi:10.1371/journal.pgen.1000901

Original File name: Journal.pgen.1000901.g003.png