We thank M Takeichi, P Coulombe, G Longmore, and L Gold for sharing their antibodies, and AG de Herreros for the Snail construct. L Degenstein and L Polak from the Fuchs laboratory provided outstanding technical assistance with transgenic work and animal husbandry. T Doetschman and Y Chai are acknowledged for the TGF-β2 KO and K14-Smad2 mice, respectively. We thank additional members of the Fuchs lab for generously sharing their reagents and ideas. CJ was partially supported by a fellowship from the Helen Hay Whitney Foundation. EF is an investigator at the Howard Hughes Medical Institute. This work was supported by the Howard Hughes Medical Institute and a grant from the National Institutes of Health.
Competing interests. The authors have declared that no competing interests exist.  Author contributions. CJ and EF conceived and designed the experiments. CJ, PL, and PK performed the experiments. CJ and EF analyzed the data. MA, RH, YC, and EF contributed reagents/materials/analysis tools. CJ and EF wrote the paper.
Note Added in Proof
Our results are particularly interesting in light of the recent implication that GSK-3β controls Snail's stability and subcellular localization [50]. Since Wnts are known to deactivate GSK-3β, Wnt and TGF-β2 signaling may contribute to Snail's transient induction and accumulation. Moreover, since inhibition of GSK-3β results in Snail upregulation and E-cadherin downregulation, Snail and GSK-3β may function at a crossroads in controlling hair bud development.
Citation: Jamora C, Lee P, Kocieniewski P, Azhar M, Hosokawa R, et al. (2004) A signaling pathway involving TGF-β2 and Snail in hair follicle morphogenesis. PLoS Biol 3(1): e11.
Abbreviations
AJ adherens junction
BMP bone morphogenic protein
EMT epithelial to mesenchymal transition
E[number] embryonic day [number]
FGF fibroblast growth factor
Grb-2 growth factor receptor-bound protein-2
HA hemaglutinin
K1 keratin 1
K5 keratin 5
KO knockout
LEF-1 lymphoid enhancer factor-1
LIM Lin-1
MAPK mitogen-activated protein kinase
ORS outer root sheath
pMAPK phosphorylated MAPK
P[number] postnatal day [number]
pSMAD phosphorylated SMAD
Shh sonic hedgehog
SMADs small phenotype– and mothers against decapentaplegic–related proteins
Sos son of sevenless
SOX  Sry-type HMG box
TCF T cell factor
Tg transgenic
TGF-β transforming growth factor β
TOP TCF-optimal-promoter
UTR untranslated region
WT wild-type