Xenbase Image ID: 130949

FIG. 2. BMP dependence of XAP-2 expression. (A) Effect of chordin expression. Fertilized eggs were injected with 250 pg of RNA encoding chordin, then ectodermal explants were dissected at stage 7/8 and cultured until sibling embryos reached late gastrula (st12.5). RNA was extracted and probed by Northern blot using cDNAs for XAP-2, Zic-r1, or EF1 as a control. Chordin injection inhibited XAP-2 and simultaneously induced expression of the neural plate marker Zic-r1. (B) Requirement for protein synthesis. Embryos were cultured in calcium/magnesium-free medium beginning at early cleavage stage (16/32-cell), and vitelline envelopes removed to facilitate continuous dissociation and dispersion, a procedure which blocks cell-cell communication (Sargent et al., 1986). Dispersed cells were divided into four pools. Protein synthesis was inhibited in two of the pools by treatment in 10 g/ml cycloheximide beginning at the equivalent of stage 7/8 (CHX ). After 15 min, 50 ng/ml recombinant human BMP4 protein (Research Diagnostics, Inc., Flanders, NJ) was added to two pools (BMP ), Ca2 and Mg2 restored to 1 mM each, and the cells cultured until stage 11. RNA was prepared and analyzed by Northern blot, using probes for XAP-2, Dlx3, Msx1, and EF1 as a control for general inhibition of protein synthesis by the CHX treatment. XAP-2 RNA induction by BMP was inhibited by CHX treatment, indicating indirect activation by this signaling pathway. Image published in: Luo T et al. (2002) Copyright © 2002. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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