Xenbase Image ID: 82511

Figure 5. Endogenous Xlet-7 discriminates mesoderm and endoderm by repressing Xacvr1b. (A) Diagram of the TP loss-of-function strategy to block interaction of the miR with the mRE in vivo. (B) Either Xlet-7 TP or control morpholinos were injected equatorially into two blastomeres on one side of four-cell stage embryos. (C,D) Unilaterally injected embryos (as in B) cultured to gastrula stage (stage 10.5), bisected transversely, and probed for Xacrv1b (C) and XleftyA (D) expression. Injection of Xlet-7 TP morpholino up-regulated and expanded the domains of Xacrv1b and XleftyA expression in the marginal zone mesoderm and underlying deep endoderm. (E) Xlet-7 TP injection up-regulated Xnr-1, Xnr-2, Xnr-3, and Xnr-4 as well as XleftyA by qRTCR on dissected lateral marginal zone explants relative to the control morpholino, which has no effect on development or gene expression. (F) Unilateral Xlet-7 TP morpholino injection repressed a marker of mesoderm, Xbra (F), while concomitantly expanding the domain of endodermal marker genes Xsox17α (G) and Xfoxa2 (H) into the mesoderm domain. (I,J) Unilateral control morpholino injection had no effect on both mesodermal (I) and endodermal (J) markers. (K,L) qRTCR analyses on dissected lateral marginal zone explants show that the Xlet-7 TP morpholino up-regulated expression of endodermal genes (XSox17α, Xfoxa2, and Xmixer) (K) and repressed mesodermal genes (Xbra, XmyoD, and Xwnt8) (L) as compared with the control morpholino. Image published in: Colas AR et al. (2012) Copyright © 2012. Image reproduced on with permission of the Publisher, Cold Spring Harbor Laboratory Press. This is an Open Access article. Larger Image Printer Friendly View

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