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Presenting Author(s) Ulrich Rüther
Abstract Title Function of Gli3 in AP patterning of limb buds.
Full author List Patrick Hill & Ulrich Rüther
Text of abstract Xt/Xt embryos which carry a null mutation of the Gli3 gene show a severe polydactyly of fore and hind limbs and a second Shh domain at the anterior side. Detailed investigation of limb buds digits has provided evidence that the anteroposterior asymmetry is only rudimentarily present. Surprisingly, this effect on AP polarity is independent of Shh, since this phenotype is also found in Shh-/-;Gli3-/- embryos (Litingtung et al. & te Welscher et al. 2002). Shh-/- embryos show fore and hind limbs with only one or two digits. For Shh-/- embryos these findings were interpreted as consequence of the presence of the Gli3 repressor form (Gli3R) in the entire limb field. In wild type limb buds Shh inhibits the proteolytic cleavage of the full length Gli3 into Gli3R (Wang et al.2000). We have recently generated a novel Gli3 mouse allele (Gli3D699) which expresses only the Gli3R protein (Böse et al. 2002). Gli3D699/Xt embryos display a polydactyly which is identical to Xt/Xt concerning digits number. Interestingly, we cannot find a second Shh domain and AP polarity is unaltered. Thus, Gli3R is essential for the AP axis in limb bud patterning and full length Gli3 protein for normality of digits number. Currently, we are analysing Shh-/-; Gli3D699/Xt embryos to test whether this effect is independent of Shh. Results will be presented on the meeting.
Which session is your work most relevant to: Limb patterning