... at the animal pole. Asc1l is a bHLH protein involved in neural development, but its maternal function has not been studied. Here, we performed a series of gain- and loss-of-function experiments on maternal ascl1 , and present three novel findings. First, Ascl1 is a repressor of mesendoderm induced by VegT...

... genes characteristic of endoderm regulated by maternal VegT, including Xsox17 α, Bix4, Mixer, GATA4 and Edd . We further demonstrate that Pumilio specifically binds VegT RNA in vitro and represses, along with Nanos1, VegT translation within PGCs. Repressed VegT RNA in wild-type PGCs is significantly...

... (Xnr) genes, except for Xnr4 , and overall increased Nodal signaling. Injection of a Nodal antagonist, Cerberus-short , reduced the severity of head and axial defects in Zic2 -depleted embryos. Depletion of Zic2 could not restore Xnr expression to embryos additionally depleted of VegT, a T-domain...

... in the literature. Sox17αexpression was first detected at stage 8 in comparison to GATA4 and 6 at stage 9 and zygotic GATA5 at stage 10. This timing of Sox17α expression correlates with previously published accounts and its proposed initial activation by the maternal T-box protein, VegT( Clements et al., 2001...

...Matt Kofron; Chris Wylie; Janet Heasman The transcription factor VegT, is required in early Xenopus embryos for the formation of both the mesoderm and endoderm germ layers. Inherited as a maternal mRNA localized only in vegetal cells, VegT activates the transcription of a large number...

... consisting only of atypical epidermis. We tried to restore complete embryonic development in PBEs by cytoplasmic transplantation or by mRNA injection. We show a two-step reconstruction of the body plan. In the first step, PBEs injected with either marginal cytoplasm or synthetic VegT RNA restored...

... to its competition with β-catenin-regulated TCF-type transcription factors for specific DNA binding sites, but rather to SOX3 binding to sites within the promoter of the early VegT- andβ-catenin-regulated dorsal-mesoderm-inducing gene Xnr5 . Although B1-type SOX proteins, such as XSOX3, are commonly...

.... 2003 Zebrafish T-box eomesodermin Maternal VegT Nodal squint bozozok goosecoid chordin floating head nieuwkoid/dharma In many organisms, maternal mRNAs and proteins are localized to specific regions of the egg and influence the development of the embryo following...

...Douglas W. Houston; Christopher Wylie One of the earliest lineage restriction events in embryogenesis is the specification of the primary germ layers: ectoderm, mesoderm and endoderm. In Xenopus , germ layer specification occurs prior to gastrulation and requires the transcription factor VegT both...

..., reinforcing the view that it functions as a secreted factor required for proper formation of posterior structures. Analysis of the derrière promoter shows that expression of the gene is controlled through a complex inductive network involving VegT and TGFβ-related molecules and also, perhaps, FGF family...

... VegT . Dorsal genes normally repressed by XTcf3 are not activated in these embryos. These data show that normal dorsal gene expression in the embryo requires the transcriptional activator VegT, whilst XTcf3 prevents their inappropriate expression on the ventral side of the embryo. †Author...

...Jennifer B. Xanthos; Matthew Kofron; Qinghua Tao; Kyle Schaible; Christopher Wylie; Janet Heasman Since the three main pathways (the Wnt, VegT and BMP pathways) involved in organizer and axis formation in the Xenopus embryo are now characterized, the challenge is to understand their interactions...

...Sharon L. Amacher; Bruce W. Draper; Brian R. Summers; Charles B. Kimmel T-box genes encode transcriptional regulators that control many aspects of embryonic development. Here, we demonstrate that the mesodermally expressed zebrafish spadetail ( spt ) /VegT and no tail ( ntl ) /Brachyury T-box genes...

... box proteins Xbra, VegT and Eomesodermin resides in the DNA-binding domain, or T box. Binding site selection experiments show that the three proteins bind the same core sequence, but they select paired sites that differ in their orientation and spacing. Lysine 149 of Xbra is conserved in all Brachyury...

...Jennifer B. Xanthos; Matt Kofron; Chris Wylie; Janet Heasman ABSTRACT During cleavage stages, maternal VegT mRNA and protein are localized to the Xenopus embryo’s vegetal region from which the endoderm will arise and where several zygotic gene transcripts will be localized. Previous loss...

... in the cell-dissociated embryos. The expression of Xnr5 and Xnr6 is regulated by maternal VegT and β -catenin , but does not require TGF-β signaling. Therefore, expression of Xnr5 and Xnr6 is controlled by different mechanisms from other Xnr family genes. * These authors contributed equally...

...-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 contrast to the Drosophila mutations, gain-of-function analysis...

.... In this study, we have investigated the regulation of the early phase of expression of Xnr1 . We show that the T-box transcription factor VegT can induce Xnr1 . It had previously been shown that Xnr1 can induce VegT in ectoderm cells and we show that the early expression of Xnr1 is regulated...

... gradient of Xnrs. Xnr expression at blastula can be activated by the vegetal determinants VegT and Vg1 acting in synergy with dorsal β-catenin. The data support a modified model for mesoderm induction in Xenopus , in which mesoderm induction is mediated by a gradient of multiple Nodal-related signals...

...Matt Kofron; Teresa Demel; Jenny Xanthos; Jamie Lohr; Benjamin Sun; Hazel Sive; Shin-Ichi Osada; Chris Wright; Chris Wylie; Janet Heasman The maternal transcription factor VegT is important for establishing the primary germ layers in Xenopus . In previous work, we showed that the vegetal masses...