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(==Model of Tbx2 function in the posterior hindlimb mesenchyme== (A) During normal limb bud outgrowth (E10.5) the expression domains of Shh (red), Grem1 (yellow) and Fgf4/9/17 (green) are in close proximity allowing propagation of the e-m signaling loo...)
 
 
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==Model of Tbx2 function in the posterior hindlimb mesenchyme==
==Model of Tbx2 function in the posterior hindlimb mesenchyme==


(A) During normal limb bud outgrowth (E10.5) the expression domains of Shh (red), Grem1 (yellow) and Fgf4/9/17 (green) are in close proximity allowing propagation of the e-m signaling loop. Following proliferative expansion of ZPA-derived cells, a broadened Tbx2 expression (blue) causes Grem1 repression. Progressive displacement of Grem1-secreting cells from the AER terminates e-m signaling (E11.5, dotted arrows). The diagrams illustrate these dynamic signaling activities. (B) Failure of Grem1 repression in Tbx2-deficient hindlimbs causes prolonged e-m signaling. The dotted line shows the posterior limit of Grem1 expression in the wild-type. Impaired termination of outgrowth reduces apoptosis and causes expansion of the digit4 condensation (E12.5, grey regions).
During normal limb bud outgrowth ({{ME10.5}}) the expression domains of Shh (red), Grem1 (yellow) and Fgf4/9/17 (green) are in close proximity allowing propagation of the e-m signaling loop. Following proliferative expansion of ZPA-derived cells, a broadened Tbx2 expression (blue) causes Grem1 repression. Progressive displacement of Grem1-secreting cells from the AER terminates e-m signaling ({{ME11.5}}, dotted arrows). The diagrams illustrate these dynamic signaling activities. Failure of Grem1 repression in Tbx2-deficient hindlimbs causes prolonged e-m signaling.  




:'''Links:''' [[Musculoskeletal System - Limb Development|Limb Development]] | {{TBX}} | {{Mouse}}
<br>
{{Tbx family collapsetable}}
===Reference===
===Reference===


<pubmed>23633963<pubmed>| [http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1003467 PLoS Genet.]
{{#pmid:23633963}}
 


====Copyright====
====Copyright====
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Figure 7. doi:10.1371/journal.pgen.1003467.g007 Original figure cropped, adjusted in size and labelling.
Figure 7. doi:10.1371/journal.pgen.1003467.g007 Original figure cropped, adjusted in size and labelling.


 
{{Footer}}
PLoS Genet. 2013;9(4):e1003467. doi: 10.1371/journal.pgen.1003467. Epub 2013 Apr 25.
[[Category:Mouse]][[Category:Limb]][[Category:Tbx]][[Category:Cartoon]]
Tbx2 terminates shh/fgf signaling in the developing mouse limb bud by direct repression of gremlin1.
[[Category:Mouse E10.5]][[Category:Mouse E11.5]][[Category:Mouse E12.5]]
Farin HF1, Lüdtke TH, Schmidt MK, Placzko S, Schuster-Gossler K, Petry M, Christoffels VM, Kispert A.
Author information
Abstract
Vertebrate limb outgrowth is driven by a positive feedback loop that involves Sonic hedgehog (Shh) and Gremlin1 (Grem1) in the posterior limb bud mesenchyme and Fibroblast growth factors (Fgfs) in the overlying epithelium. Proper spatio-temporal control of these signaling activities is required to avoid limb malformations such as polydactyly. Here we show that, in Tbx2-deficient hindlimbs, Shh/Fgf4 signaling is prolonged, resulting in increased limb bud size and duplication of digit 4. In turn, limb-specific Tbx2 overexpression leads to premature termination of this signaling loop with smaller limbs and reduced digit number as phenotypic manifestation. We show that Tbx2 directly represses Grem1 in distal regions of the posterior limb mesenchyme allowing Bone morphogenetic protein (Bmp) signaling to abrogate Fgf4/9/17 expression in the overlying epithelium. Since Tbx2 itself is a target of Bmp signaling, our data identify a growth-inhibiting positive feedback loop (Bmp/Tbx2/Grem1). We propose that proliferative expansion of Tbx2-expressing cells mediates self-termination of limb bud outgrowth due to their refractoriness to Grem1 induction.
PMID: 23633963

Latest revision as of 09:43, 5 April 2019

Model of Tbx2 function in the posterior hindlimb mesenchyme

During normal limb bud outgrowth (E10.5) the expression domains of Shh (red), Grem1 (yellow) and Fgf4/9/17 (green) are in close proximity allowing propagation of the e-m signaling loop. Following proliferative expansion of ZPA-derived cells, a broadened Tbx2 expression (blue) causes Grem1 repression. Progressive displacement of Grem1-secreting cells from the AER terminates e-m signaling (E11.5, dotted arrows). The diagrams illustrate these dynamic signaling activities. Failure of Grem1 repression in Tbx2-deficient hindlimbs causes prolonged e-m signaling.


Links: Limb Development | TBX | mouse


Human TBX Family  
Table - Human Tbx Family
Approved
Symbol
Approved Name Previous Symbols Synonyms Chromosome
TBX1 T-box 1 VCF CATCH22 22q11.21
TBX2 T-box 2 17q23.2
TBX3 T-box 3 UMS "TBX3-ISO, XHL" 12q24.21
TBX4 T-box 4 17q23.2
TBX5 T-box 5 HOS 12q24.21
TBX6 T-box 6 16p11.2
TBX10 T-box 10 TBX7 TBX13 11q13.2
TBX15 T-box 15 TBX14 1p12
TBX18 T-box 18 6q14.3
TBX19 T-box 19 "dj747L4.1, TPIT" 1q24.2
TBX20 T-box 20 7p14.2
TBX21 T-box 21 "TBLYM, T-bet" 17q21.32
TBX22 T-box 22 "CPX, CLPA" Xq21.1
TBX23P T-box 23, pseudogene TBX23 1q25
TBR1 T-box, brain 1 2q24.2
EOMES eomesodermin TBR2 3p24.1
MGA MGA, MAX dimerization protein "KIAA0518, MAD5, MXD5, FLJ12634" 15q15
TBXT T-box transcription factor T T 6q27
    Links: Developmental Signals - Tbx | OMIM Tbx3 | HGNC | Bmp Family | Sox Family | Tbx Family

Reference

Farin HF, Lüdtke TH, Schmidt MK, Placzko S, Schuster-Gossler K, Petry M, Christoffels VM & Kispert A. (2013). Tbx2 terminates shh/fgf signaling in the developing mouse limb bud by direct repression of gremlin1. PLoS Genet. , 9, e1003467. PMID: 23633963 DOI.

Copyright

© 2013 Farin et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Figure 7. doi:10.1371/journal.pgen.1003467.g007 Original figure cropped, adjusted in size and labelling.


Cite this page: Hill, M.A. (2024, April 23) Embryology Hindlimb Tbx2 model.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Hindlimb_Tbx2_model.jpg

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G

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current10:48, 7 December 2014Thumbnail for version as of 10:48, 7 December 20141,000 × 607 (84 KB)Z8600021 (talk | contribs)==Model of Tbx2 function in the posterior hindlimb mesenchyme== (A) During normal limb bud outgrowth (E10.5) the expression domains of Shh (red), Grem1 (yellow) and Fgf4/9/17 (green) are in close proximity allowing propagation of the e-m signaling loo...

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