..., the current study identifies and characterizes Vg1/Nodal signaling (henceforth referred to as ‘Nodal-like signaling’) as a novel regulator of IM formation. Excess Nodal-like signaling at gastrulation stages resulted in expansion of the IM at the expense of the adjacent paraxial mesoderm, whereas inhibition...

..., but different vertebrates differ in how this activity is positioned. In chick, the earliest known asymmetry is posterior expression of the TGFβ-related factor Vg1, close to the future Nodal expression domain. Here we show that the transcription factor Gata2 is expressed anteriorly before this stage. Gata2...

... critically requires autoregulation by Nodal and signaling by the maternal TGF-β Univin. We show that Univin is related to Vg1, that both Nodal and Univin signal through Alk4/5/7, and that zygotic expression of univin , like that of nodal , is dependent on SoxB1 function and Tcf/β-catenin signaling. This work...

...Kunimasa Ohta; Sei Kuriyama; Tatsuya Okafuji; Ryu Gejima; Shin-ichi Ohnuma; Hideaki Tanaka Three classes of signaling molecule, VG1, WNT and BMP, play crucial roles in axis formation in the chick embryo. Although VG1 and WNT signals have a pivotal function in inducing the primitive streak...

...Bilge Birsoy; Matt Kofron; Kyle Schaible; Chris Wylie; Janet Heasman Xenopus Vg1, a transforming growth factor β (Tgfβ)family member, was one of the first maternally localized mRNAs identified in vertebrates. Its restriction to the vegetal pole of the egg made it the ideal candidate...

... hemisphere of the oocyte; second, it is required for the endogenous mesoderm inducing activity of vegetal cells before gastrulation; and third, it has substrate-specific activity, cleaving Xnr1, Xnr2, Xnr3 and Vg1, but not Xnr5,Derrière or ActivinB pro-proteins. We conclude that maternal XPACE4 plays...

... pathways that initiate primitive streak formation and the mechanisms that ensure that only a single axis normally forms. As reported previously, an ectopic primitive streak can be induced by misexpression of Vg1 in the marginal zone. We now show that Vg1 induces an inhibitor that travels across the embryo...

...-catenin (Wnt proteins), MAPK (tyrosine kinase receptors/FGF), Smad1 (BMP proteins) and Smad2 (Nodal/activin/Vg1). We have determined semi-quantitatively the distribution of these components at 18 consecutive stages in Xenopus development, from early blastula to tailbud stages, by immunofluorescence...

... the PMZ is removed, the embryo can initiate axis formation from another part of the remaining marginal zone. Chick Vg1 can mimic the axis-inducing ability of the PMZ, but only when misexpressed somewhere within the marginal zone. We have investigated the properties that define the marginal zone...

...Tetsuya Kitaguchi; Takeharu Nagai; Katsunori Nakata; Jun Aruga; Katsuhiko Mikoshiba ABSTRACT Establishment of left-right (L-R) asymmetry is fundamental to vertebrate development. Several genes involved in L-R asymmetry have been described. In the Xenopus embryo, Vg1 / activin signals are implicated...

...-binding domain of the protein. In contrast to the two other known maternally encoded endoderm inducers, Vg1 and VegT, xBic-C ectopic expression leads specifically to endoderm formation in the absence of mesoderm induction. In Xenopus , the first 6 to 7 hours of development rely completely...

..., designated Cer-S, provides a specific secreted antagonist of mesoderm-inducing Xenopus Nodal-Related (Xnr) factors. Cer-S does not inhibit signalling by other mesoderm inducers such as Activin, Derrière, Vg1 and BMP4, nor by the neural inducer Xnr3. In the present study we show that Cer-S blocks...

...Ann F. Ramsdell; H. Joseph Yost The rightward looping of the primary heart tube is dependent upon upstream patterning events that establish the vertebrate left-right axis. In Xenopus , a left-sided Vg1 signaling pathway has been implicated in instructing cells to adopt a ‘left-sided identity...

... , a novel TGF-β family member that is closely related to Vg1 and that is required for normal mesodermal patterning, particularly in posterior regions of the embryo. Unlike Vg1, derrière is expressed zygotically, with RNA localized to the future endoderm and mesoderm by late blastula, and to the posterior...

...Elaine M. Joseph; Douglas A. Melton ABSTRACT The Xenopus Vg1 gene, a TGFβ superfamily member, is expressed as a maternal mRNA localized to prospective endoderm, and mature Vg1 protein can induce both endodermal and mesodermal markers in embryonic cells. Most previous work on embryonic inducers...

... . Development 115 , 573 – 585 . 10.1242/dev.115.2.573 Dale , L. , Matthews , G. and Colman , A. ( 1993 ). Secretion and mesoderm-inducing activity of the TGF-beta-related domain of Xenopus Vg1 . EMBO J . 12 , 4471 – 4480 . 10.1002/j.1460-2075.1993.tb06136.x Derynck...

...Daniel S. Kessler; Douglas A. Melton ABSTRACT Mesoderm induction during Xenopus development has been extensively studied, and two members of the transforming growth factor-β family, activin βB and Vg1, have emerged as candidates for a natural inducer of dorsal mesoderm. Heretofore, analysis of Vg1...

...Joel K. Yisraeli; Sergei Sokol; D. A. Melton In an effort to understand how polarity is established in Xenopus oocytes, we have analyzed the process of localization of the maternal mRNA, vg1. In fully grown oocytes, vg1 mRNA is tightly localized at the vegetal cortex. Biochemical fractionation...