Tbx5 and Tbx4 genes determine the wing/leg identity of limb buds.
Much progress has been made in understanding limb development. Most genes are expressed equally and in the same pattern in the fore- and hindlimbs, which nevertheless develop into distinct structures. The T-box genes Tbx5 and Tbx4, on the other hand, are expressed differently in chick wing (Tbx5) and leg (Tbx4) buds. Molecular analysis of the optomotor blind gene, which belongs to the same family of transcription factors, has revealed that this gene is involved in the transdetermination of Drosophila wing and leg imaginal discs. In addition, expression of Tbx5 and Tbx4 correlates well with the identity of ectopic limb buds induced by fibroblast growth factor. Thus, it is thought that Tbx5 and Tbx4 might be involved in determining limb identity. Another candidate is the Pitx1 gene, which encodes a bicoid-type homeodomain transcription factor that is expressed in leg buds. Here we determine the importance of these factors in establishing limb identity.
Takeuchi
J K
JK
Nara Institute of Science and Technology Graduate School of Biological Sciences, Ikoma, Japan.
Koshiba-Takeuchi
K
K
Matsumoto
K
K
Vogel-Höpker
A
A
Naitoh-Matsuo
M
M
Ogura
K
K
Takahashi
N
N
Yasuda
K
K
Ogura
T
T
D000818:Animals; D030161:Avian Proteins; D002642:Chick Embryo; D003001:Cloning, Molecular; D018274:Electroporation; D004625:Embryo, Nonmammalian / Q000502:physiology; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D006614:Hindlimb / Q000196:embryology; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology; D006801:Humans; D018878:Limb Buds / Q000196:embryology; D008164:Luminescent Proteins; D009024:Morphogenesis / Q000502:physiology; D051761:Paired Box Transcription Factors; D011993:Recombinant Fusion Proteins; D020825:T-Box Domain Proteins; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology; D014921:Wings, Animal / Q000196:embryology
D030161:Avian Proteins; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D051761:Paired Box Transcription Factors; D011993:Recombinant Fusion Proteins; D020825:T-Box Domain Proteins; C103172:T-box transcription factor 5; C491196:TBX4 protein, Gallus gallus; C491193:TBX4 protein, human; D014157:Transcription Factors; C101485:homeobox protein PITX1; D049452:Green Fluorescent Proteins