Storrs Wingless - 2

Origin & History: Found in White Leghorn stock; Zwilling, E 1956 J Exp Zool 132:241-253; held at Storrs since that time.

Breed: Single Comb White Leghorn

Symbol: wg-2

Characteristics: Autosomal recessive, embryonic lethal

Description: Homozygotes lack wings, have reduced legs, balloon-like feathers, short upper beak, cleft palate and small kidneys.

                                           wg/wg

Additional Information: Outgrowth of limb buds is initiated but development of the apical ectodermal ridge is not sustained and the limb buds fail to elongate normally.Wingless embryos are readily identified on the fourth day of incubation because of the very small size and irregularity of the wing buds. As in the case of normal limb buds deprived of their AER, explanted wg-2 limb buds, can undergo proliferation and directed outgrowth in the presence of exogenous IGF-1 or insulin, and to a lesser extent FGF-2 or FGF-4. The thin apical ectoderm of the mutant limb buds is induced to form thickened AER-like structures that can express high levels of Msx-2, a marker for AER function, by treatment with IGF-1 and insulin. (Development 122:1323-1330, 1996) Other gene products also stimulate enhanced outgrowth of ll limb buds and expression of appropriate genes under various experimental conditions:

(Development 122:3851-3861, 1996): Implants of beads soaked with Fgf-8 - Shh

(Dev Biol 184:343-350, 1997): FGF-2 supplemented culture medium - syndecan-3

(Dev Biol 202:43-55, 1998): TGF-alpha or EGF supplemented serum-free defined medium - Msx2, Bmp-2, Wnt7a but not Fgf-8, Fgf-4, Bmp-4 or Shh

Gene expression associated with initiation of limb bud outgrowth has been described for the following:

(Growth Hormone & IGF Res 11:346-363, 2001): IGF-1, IGFBP2

(Dev Biol 202:43-55, 1998): TGF-alpha, EGF, c-erb B

Frizzled-7, Frizzled-3, Frizzled-6, Lef-1, Tcf-1, Axin, B-catenin