FGF and genes encoding transcription factors in early limb specification.
SnR, twist and Fgf10 are expressed in presumptive limb territories of early chick embryos. When FGF-2/FGF-8 beads are implanted in chick flank, an ectopic limb develops and SnR is irreversibly activated as early as 1 h. Ectopic Fgf10 and twist expression are activated much later at 17 and 20 h, respectively. FGF-10 can also induce SnR, but much later, and in this case activation occurs simultaneously with that of twist and Fgf10 via the Fgf8- expressing ridge. Tbx-4 and Tbx-5 are expressed in leg and wing forming regions, respectively, in a similar pattern to SnR and twist. FGF-2 leads to ectopic expression of Tbx-4 and Tbx-5 as rapidly as ectopic expression of SnR, but the patterns of ectopic transcripts suggest that induction of SnR and Tbx gene expression occur via different pathways.
Isaac
A
A
Department of Anatomy and Developmental Biology, University College London, UK. a.j.isaac@dundee.ac.uk
Cohn
M J
MJ
Ashby
P
P
Ataliotis
P
P
Spicer
D B
DB
Cooke
J
J
Tickle
C
C
D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D002642:Chick Embryo; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics*; D005121:Extremities / Q000196:embryology; D051526:Fibroblast Growth Factor 10; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000235:genetics* / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D008969:Molecular Sequence Data; D000071250:Snail Family Transcription Factors; D020825:T-Box Domain Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D051879:Twist-Related Protein 1
D030161:Avian Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051526:Fibroblast Growth Factor 10; D000071250:Snail Family Transcription Factors; D020825:T-Box Domain Proteins; C103172:T-box transcription factor 5; C491196:TBX4 protein, Gallus gallus; D014157:Transcription Factors; C412362:Twist protein, Gallus gallus; D051879:Twist-Related Protein 1; C104481:snail-related protein, Gallus gallus; D016222:Fibroblast Growth Factor 2; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors