Yoon J , Kim JH , Lee SY , Kim S , Park JB , Lee JY , Kim J .

	Fig. 1. bFGF induces PV.1 expression. (A) Ectodermal explants were dissected at stage 8 and incubated in animal cap media containing bFGF (50 ng/ml) until stage 11 or 24. The relative gene expression was analyzed by RT-PCR. (B) Ectodermal explants were dissected at stage 8 and incubated in animal cap media containing either bFGF alone or bFGF and CHX (5 ng/ml) until stage 11. The relative gene expression was analyzed by RT-PCR. The graph indicates the band intensity of PV.1 (right panel). ODC, loading control; no RT, control reaction without reverse transcriptase; WE, whole-embryo positive control; Xbra, pan-mesoderm marker; chordin, dorsal mesoderm marker; PV.1, GATA2, and XVent-1a, ventral-specific markers; Zic3, early neural marker; NCAM, pan-neural marker; OTX2, anterior neural marker; HoxB9, posterior neural marker; Krox20, mid-brain marker; muscle actin (M. Actin), late dorsal mesoderm marker.
	Fig. 2. DN-Xbra reduces the expression of target genes downstream of BMP. (A) Xbra RNA (1 ng) was injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated until stage 11. The relative gene expression was analyzed by RT-PCR. (B) DNBR RNA (1 ng) and Xbra RNA (1 ng) were co-injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated until stage 11. The relative gene expression was analyzed by RT-PCR. (C) Xbra RNA (1 ng) was injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated in animal cap media containing CHX (5 ng/ml) until stage 11 or 24. The relative gene expression was analyzed by RT-PCR. The data shown represent the means ± the S.D.s from at least three independent experiments. The differences were considered significant at P＜ 0.05.
	Fig. 3. Xbra directly induces PV.1 expression. (A) Schematic representation of Xbra and DN-Xbra. Xbra and DN-Xbra have a DNA-binding domain (T-box), but DN-Xbra has an engrailed repressor domain instead of a transcriptional activation domain in the C-terminal region. (B) DN-Xbra RNA (2, 1, or 0.5 ng) was injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated until stage 11 or 24. The relative gene expression was analyzed by RT-PCR. (C) Smad1 RNA (2, 1, or 0.5 ng) and DN-Xbra RNA (2 ng) were co-injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated until stage 11 or 24. The relative gene expression was analyzed by RT-PCR. (D) DN-Xbra RNA (2 ng) was injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated in animal cap media containing CHX (5 ng/ml) until stage 11 or 24. The relative gene expression was analyzed by RT-PCT. Noggin, dorsal mesoderm marker; Mixer, Sox17b, and Edd, endoderm markers; Xk81, epidermis marker; globin, blood marker; CG13, cement glad marker. The data are shown as the means ± the S.D.s of the values of at least three independent experiments. Differences were considered significant at P＜ 0.05.
	Fig. 4. The knockdown of PV.1 induces neurogenesis in bFGF-treated ectodermal explants. (A) PV.1 RNA (0.5 ng) and DN-Xbra RNA (2 ng) were co-injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated until stage 11 or 24. The relative gene expression was analyzed by PCR. (B) Anti-sense morpholino oligos of PV.1 (20 ng) were injected at the one-cell stage. Ectodermal explants were dissected at stage 8 and incubated in animal cap media containing bFGF (50 ng/ml) until stage 11 or 24. The relative gene expression was analyzed by RT-PCR.

Amaya, Expression of a dominant negative mutant of the FGF receptor disrupts mesoderm formation in Xenopus embryos. 1991, Pubmed, Xenbase

Amaya, Expression of a dominant negative mutant of the FGF receptor disrupts mesoderm formation in Xenopus embryos. 1991, Pubmed , Xenbase
Amaya, FGF signalling in the early specification of mesoderm in Xenopus. 1993, Pubmed , Xenbase
Cooke, Induction and the organization of the body plan in Xenopus development. 1989, Pubmed , Xenbase
Dale, A gradient of BMP activity specifies dorsal-ventral fates in early Xenopus embryos. 1999, Pubmed , Xenbase
Dale, Bone morphogenetic protein 4: a ventralizing factor in early Xenopus development. 1992, Pubmed , Xenbase
Dale, BMP signalling in early Xenopus development. 1999, Pubmed , Xenbase
Delaune, Neural induction in Xenopus requires early FGF signalling in addition to BMP inhibition. 2005, Pubmed , Xenbase
Friedle, Cooperative interaction of Xvent-2 and GATA-2 in the activation of the ventral homeobox gene Xvent-1B. 2002, Pubmed , Xenbase
Gawantka, Antagonizing the Spemann organizer: role of the homeobox gene Xvent-1. 1995, Pubmed , Xenbase
Green, Growth factors as morphogens: do gradients and thresholds establish body plan? 1991, Pubmed , Xenbase
Hemmati-Brivanlou, Inhibition of activin receptor signaling promotes neuralization in Xenopus. 1994, Pubmed , Xenbase
Hwang, Active repression of organizer genes by C-terminal domain of PV.1. 2003, Pubmed , Xenbase
Hwang, Antimorphic PV.1 causes secondary axis by inducing ectopic organizer. 2002, Pubmed , Xenbase
Isaacs, Expression of a novel FGF in the Xenopus embryo. A new candidate inducing factor for mesoderm formation and anteroposterior specification. 1992, Pubmed , Xenbase
Kim, Mesoderm induction by heterodimeric AP-1 (c-Jun and c-Fos) and its involvement in mesoderm formation through the embryonic fibroblast growth factor/Xbra autocatalytic loop during the early development of Xenopus embryos. 1998, Pubmed , Xenbase
LaBonne, Mesoderm induction by activin requires FGF-mediated intracellular signals. 1994, Pubmed , Xenbase
Lee, Direct response elements of BMP within the PV.1A promoter are essential for its transcriptional regulation during early Xenopus development. 2011, Pubmed , Xenbase
Messenger, Functional specificity of the Xenopus T-domain protein Brachyury is conferred by its ability to interact with Smad1. 2005, Pubmed , Xenbase
Pera, Integration of IGF, FGF, and anti-BMP signals via Smad1 phosphorylation in neural induction. 2003, Pubmed , Xenbase
Rao, Conversion of a mesodermalizing molecule, the Xenopus Brachyury gene, into a neuralizing factor. 1994, Pubmed , Xenbase
Rogers, Neural induction and factors that stabilize a neural fate. 2009, Pubmed , Xenbase
Schneider-Poetsch, Inhibition of eukaryotic translation elongation by cycloheximide and lactimidomycin. 2010, Pubmed
Schulte-Merker, Mesoderm formation in response to Brachyury requires FGF signalling. 1995, Pubmed , Xenbase
Smith, Expression of a Xenopus homolog of Brachyury (T) is an immediate-early response to mesoderm induction. 1991, Pubmed , Xenbase
Smith, Dorsalization and neural induction: properties of the organizer in Xenopus laevis. 1983, Pubmed , Xenbase
Smith, Expression cloning of noggin, a new dorsalizing factor localized to the Spemann organizer in Xenopus embryos. 1992, Pubmed , Xenbase
von Dassow, Induction of the Xenopus organizer: expression and regulation of Xnot, a novel FGF and activin-regulated homeo box gene. 1993, Pubmed , Xenbase
Wesche, Fibroblast growth factors and their receptors in cancer. 2011, Pubmed
Xu, A dominant negative bone morphogenetic protein 4 receptor causes neuralization in Xenopus ectoderm. 1995, Pubmed , Xenbase
Xu, Opposite effects of FGF and BMP-4 on embryonic blood formation: roles of PV.1 and GATA-2. 1999, Pubmed , Xenbase
Yamamoto, Requirement of Xmsx-1 in the BMP-triggered ventralization of Xenopus embryos. 2000, Pubmed , Xenbase