QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

Help viewing high resolution images Return to article

Fig. 2. Misexpression of Tbx3 and Tbx3^EN causes a rostral shift in limb position but the shifted limb is patterned normally. Dorsal views of embryos; injected side is on the right, control side is on the left. Rostral is towards the top. (A) Whole-mount in situ hybridization with MyoD marking somites and Shh marking the ZPA. There is a one somite-level shift in limb position (compare level of left and right bar). (B) Whole-mount in situ hybridization with Pax3 marking migrating myoblasts from the lateral lip of dermomyotome into the limb mesenchyme. Pax3 is not detected in the lateral lip of the dermomyotome in somites at levels that normally contribute to limb musculature (black arrowhead), as these cells have migrated into the limb. Following a limb shift on the injected side, these Pax3-expresssing cells are still present in somites at the same axial level (red arrowhead). (C) Whole-mount immunohistochemistry for the neurofilament-associated antigen (3A10). Axons from axial levels that normally innervate the limb fail to send projections to the shifted limb (right, black arrowheads). At more rostral levels, following mislocation of the limb, axons that normally do not innervate the limb on the injected side, project into the limb mesenchyme (red arrowheads). (D-I) Genes expressed in regions of the limb ectoderm or mesenchyme. Fgf8 (D), Bmp2 (E), Hoxc5 (F), Tbx5 (G), Tbx15 (H) and Tbx2 (I) are all expressed in their normal pattern in the shifted limb. (J-O) Skeletal preparations of an embryo injected with Tbx3 in the wing (J-L) or in the leg (M-O). Although the wing and the leg are shifted rostrally (compare bar levels between left and right side in J and M), no alterations are observed in the vertebral column. Arrow in J indicates scapula, arrow in M indicates ischium. (K) Injected wing; (L) contralateral control wing. There is no alteration in the pattern of the limb elements. (N) Injected leg; (O) uninjected leg. No change is observed in digit patterning following Tbx3 misexpression. Chick stages: (A) 22, (B) 23, (C) 24, (D-I) 21, (J-O) 27.

Return to article