Castro Colabianchi AM , Tavella MB , Boyadjián López LE , Rubinstein M , Franchini LF , López SL .

             embryonic brain development

	Figure 1. Effects of blocking Nodal on chrd.1 (A-C, F,G) and sia1 expression (D,E) at late blastula (s9). Chrd.1 (A) and sia1 (D) are normally expressed in the whole BCNE center. Cer-S (B) and foxh1-SID (F,G) injections revealed a marginal BCNE subpopulation of cells that depends on Nodal to express the neural inducer chrd.1 (red asterisk), while its upstream regulator sia1 (E), a direct Wnt/nβ-cat target, and the animal chrd1+ subdomain in the BCNE (B,F, green asterisk), do not depend on Nodal. The foxh1-SID-injected side is evidenced by the tracer’s fluorescence (G) and is indicated by a black arrowhead. (C) RT-qPCR analysis showed a significant increase (p<0.05) in the levels of chrd.1 transcripts as a result of cer-S injection (p=0.027, unpaired, two-tailed t-test) when compared with uninjected siblings. Bars represent mean + S.E.M. of 6 biological replicates. A,B,F,G, dorsal views; D,E, animal views; an, animal; veg, vegetal; d, dorsal; v, ventral.
	Figure 2. chrd.1 expression invades the animal hemisphere during s9 and is later restricted to the gastrula organizer. (A-C) ISH of chrd.1 at s9 in a whole embryo (A) and in two different hemisected embryos obtained from an independent female (B,C). Notice the large domain of chrd.1 encompassing both animal and marginal dorsal cells. Arrowheads in (B,C) point to the animal limit of chrd.1 expression, near the animal pole. (D,E) Double ISH for chrd.1 (revealed with BCIP, cyan) and hes4 (revealed with NBT+BCIP, purplish) at s9 (D) and s10 (E). At these stages, the strongest hes4 expression is found throughout the animal hemisphere, as previously shown (Aguirre et al., 2013). Purple arrowheads in (D,E) point to the approximate limit of this strong animal hes4 domain. A large chrd.1 domain readily invades the animal hemisphere at s9 (cyan arrowheads), overlapping hes4 in the animal region, almost reaching the animal pole. At the onset of gastrulation (s10), chrd.1 does not overlap hes4 expression in the animal hemisphere, being restricted to the dorsal marginal zone (cyan arrowheads) (E). (F) Color-coded diagram illustrating the contribution of A1 to C4 blastomeres from the 32-cells stage embryo to the s9 stage embryo [modified from (Bauer et al., 1994)]. chrd.1 expression in the BCNE region (between purple arrowheads) comprises both A1 and B1 derivatives. The GO mostly derives from B1 whereas A1 mainly contributes to the neural plate (Bauer et al., 1994). (G) Distribution of nuclear phosphorylated-SMAD2 (p-SMAD2) at s9, showing that Nodal signaling is highly transduced in the dorsal-marginal and dorsal vegetal region at late blastula but not in the animal part of the BCNE area [modified from (Schohl and Fagotto, 2002). Illustrations of midsagittal sections of s9 embryos in (F,G) based on (Hausen and Riebesell, 1991). an, animal; veg, vegetal; bl, blastocoel cavity; dbl, dorsal blastopore lip.
	Figure 3. Effects of blocking Nodal on chrd.1 expression during gastrulation. (B,C,E,F) Injection of cer-S. (G-I) Unilateral injection of foxh1-SID. (A,D) Uninjected control siblings of embryos shown in (B,C) and (E,F), respectively. At early gastrula (s10), chrd.1 is expressed in the more external, pre-involuted presumptive CM cells and in the deeper, involuted presumptive PM, which are seen together as a compact domain (A, and non-injected side in G- I), but ceases expression in brain precursors (Kuroda et al., 2004). cer-S (B,C) and foxh1-SID (G- I) suppressed chrd.1 expression in the pre-involuted population (red asterisks, G-I), but did not affect (green asterisks, G-I) or even expanded (light blue asterisk, H) chrd.1+ cells in the involuted population. The foxh1-SID-injected side is evidenced by X-gal turquoise staining (G-I) and is indicated by black arrowheads. At late gastrula (s13), chrd.1 is expressed in the PM (green arrow, D) and the CM (red arrow, D). In cer-S-injected embryos, PM chrd.1 expression persisted (E,F, green arrows) but CM expression decreased (E,F, red arrows) or was arrested at the blastopore (E, yellow asterisk). All embryos are shown in dorsal views, anterior side upwards.
	Figure 4. Effects of cer-S on the PM marker gsc (A-F) and the neural marker sox2 (G-I) at the stages indicated. (A-C) After cer-S injection, gsc expression was not significantly affected at s9, as revealed by ISH (A,B) and RT-qPCR (C) (p=0.8184; unpaired, two-tailed t-test) when compared with uninjected siblings. Bars represent mean + S.E.M. of 6 biological replicates. (D- F) At the end of gastrulation, gsc expression decreased in the PM of most cer-S-embryos injected, as revealed by ISH (D,E). Gsc transcripts levels were also significantly reduced at s10 (p<0.05), as revealed by RT-qPCR (F) (p=0.0002; unpaired, two-tailed t-test) when compared with uninjected siblings. Bars represent mean + S.E.M. of 4 biological replicates. (G) Control blastula showing expression of the neural marker sox2, which was consistently increased in cer-S-injected siblings, as revealed by ISH (H). A significant increase (p<0.05) in sox2 transcripts levels was detected by RT-qPCR at s9 in cer-S-injected embryos (p=0.0016; unpaired, two- tailed t-test) when compared with uninjected siblings (I). Bars represent mean + S.E.M. of 5 biological replicates. (A,B,G,H), sagittal hemisections of s9 embryos; insets in A,B show dorsal views of whole embryos; insets in G,H show animal views of whole embryos; (D,E) dorsal views; an, animal; veg; vegetal; d, dorsal; v, ventral; bl, blastocoel cavity.
	Figure 5. Effects of cer-S on the spatial expression of the pan-mesoderm/CM marker tbxt (A-G) and the CM marker not (H-M) at the stages indicated in grey boxes. (A,C,E) Control gastrulae showing tbxt expression in the CM (red arrow), GO (yellow arrow) and presumptive ventrolateral mesoderm in the blastopore (vlm, white arrow). (B,D,F) cer-S-injected embryos which are siblings of those shown in A,C,E, respectively. (G) Summary of the effects of cer-S on tbxt expression at gastrula stage. Results are expressed as the percentage of embryos showing the indicated phenotypes for each tbxt subdomain. (H) Dorsal view of a control late blastula, showing strong not expression in the BCNE region, which decreased in cer-S-injected siblings (I). (J) Control gastrula showing not expression in the extending CM (red arrow), GO (yellow asterisk) and limit of involution (li, white arrow). Cer-S abolished not expression in the extending notochord (K,L,M) and often decreased it in the GO (K,M); when not expression was not decreased in the GO (L), not+ cells were arrested at the blastopore, unable to involute. (M) summary of the effects of cer-S on not expression at gastrula stage. Results are expressed as the percentage of embryos showing the indicated phenotypes for each not subdomain. See main text for details. (A-F,J), posterior/dorsal views. (H,I,K,L) Dorsal views.
	Figure 6. (A,B) Previous model of Wnt/nβ-cat and Nodal requirements for chrd.1 expression in the blastula and gastrula dorsal signaling centers (Wessely et al., 2001). Dorsal nβ-cat initiates chrd.1 expression in the BCNE through direct activation of the gene encoding the transcription factor Sia (Ishibashi et al., 2008). According to this model, Nodal signaling is not required to initiate chrd.1 expression in the BCNE (A), but it is later required for the maintenance of chrd.1 expression in the GO (B). (C,D) Role of Nodal and Wnt/nβ-cat in BCNE compartmentalization and the development of its derivatives updated in the present work. The expression domains of the markers analyzed in this study are color-coded. (C) Dorsal nβ- cat initiates pre-brain and prechordal pre-organizer induction through the activation of sia in the BCNE. Accumulation of nodal transcripts in the NC requires the cooperative action of VegT and dorsal nβ-cat (Takahashi et al., 2000). Dorsal nβ-cat initiates chordal pre-organizer induction through the activation of sia in the BCNE and nodal-related genes in the NC. (D) During gastrulation, high Nodal signaling maintains CM development, whereas low Nodal signaling maintains PM development.
	Fig. 7. Comparison between vertebrate models. (A) Position of the dorsal signaling centers at the blastula stage in Xenopus (dorsal view). Expression patterns were obtained from the following sources: chrd.1, (Kuroda et al., 2004); gsc, (Sudou et al., 2012); nodal(s), (Agius et al., 2000), (Takahashi et al., 2000), (Kuroda et al., 2004), (Reid et al., 2016); sia, (Sudou et al., 2012); sox2 (this work). While sia is expressed in the whole BCNE, gsc transcripts are present in a subset of BCNE cells (Sudou et al., 2012), and its expression is not perturbed by blocking Nodal (this work). The presence of different cell subpopulations in the BCNE is shown according to the response of the indicated markers to Nodal. The green arrow denotes that Nodal favors the specification of subpopulations expressing chrd.1 and not (black letters) and does not necessarily imply direct regulation of these genes. The red broken line denotes that Nodal restricts the specification of the subpopulations expressing chrd and sox2 (white letters) and does not necessarily imply direct regulation of these genes. (B, C) Fate map of the outer (A) and inner (B) cell layers of Xenopus at the onset of gastrulation (dorsal view), just before the beginning of endomesoderm internalization [adapted from (Keller, 1975), (Keller, 1976), (Shook and Keller, 2004), (Shook et al., 2004)]. A high-resolution fate map of s9 Xenopus embryos is not available, but lineage tracing experiments demonstrated that the BCNE gives rise to the forebrain and part of the midbrain and hindbrain (neurectoderm derivatives) and to the AM and floor plate (GO derivatives) (Kuroda et al., 2004). Therefore, a rough correlation of the predicted territories can be projected from the s10 map to the s9 embryo. (D) Diagram of a sphere stage zebrafish embryo, showing the expression patterns of the following markers: chrd (Sidi et al., 2003), (Branam et al., 2010); chrdl2 (Branam et al., 2010); nodal1 (squint) + nodal2 (cyclops) (Feldman et al., 1998), (Rebagliati et al., 1998). The presence of different cell subpopulations in the blastula dorsal signaling center are shown according to the response of the indicated markers to Nodal. The green arrow denotes that Nodal favors the specification of subpopulations expressing chrd and gsc (black letters) and does not necessarily imply direct regulation of these genes. Another subpopulation of chrd+ cells (white letters) does not require Nodal at blastula stage. (E) Fate map for the zebrafish CNS at the shield stage. (F) Chrd, chrdl2 and Nodal expression in zebrafish at shield stage (bibliographic references as in D). The broken line depicts the limit of the yolk cell. (G,H) Diagram illustrating a pre-streak stage chick embryo, showing Chrd and Nodal expression (G) and a rough fate map for the precursors of the CNS and GO (H). Predictions of the locations of the centers of the prospective territories of the CNS are shown in a gradient of blue colors, as there is a great overlap of cell fates at this stage [modified from (Stern et al., 2006), (Foley et al., 2000)]. The posterior cells (PC) and central cells (CC) contributing to Hensen’s node are also shown [modified from (Streit et al., 2000)]. Expression patterns were obtained from the following sources: Chrd, (Streit et al., 1998), (Matsui et al., 2008); Nodal, (Matsui et al., 2008); Gsc, (Izpisúa-Belmonte et al., 1993). Notice the proposed overlap in the territories of the prospective forebrain (dark blue) and a subset of the GO precursors (stippled orange), both expressing Chrd, which is also expressed by another population of GO precursors (PC) that also expresses Gsc. AO, area opaca; AP, area pellucida; KS, Köller’s sickle (located in the superficial part of the posterior marginal zone); GO, Hensen’s node; MZ, marginal zone. (I, J) Gastrulating mouse embryos at mid (I) and late (J) streak stages, respectively, indicating signaling centers and embryological regions. Illustrations were based on the following sources: (Tam and Behringer, 1997), (Tam et al., 1997), (Beddington and Robertson, 1999), (Kinder et al., 2001), (Yamaguchi, 2001), (Tam and Rossant, 2003), (Levine and Brivanlou, 2007), (Shen, 2007). ADE, anterior definitive endoderm; AEM, anterior endomesoderm; AVE, anterior visceral endoderm; GO, gastrula organizer; Mes, mesoderm; PM, prechordal mesoderm; PS, primitive streak (broken line); VE, visceral endoderm. Blue colors represent the progressive anterior-posterior regionalization of the neural ectoderm in the model for anterior neural induction/posteriorization proposed by (Levine and Brivanlou, 2007). (K,L) Expression patterns at mid (K) and late (L) streak stages were obtained from the following sources: Chrd, (Bachiller et al., 2000); Chrdl1, (Coffinier et al., 2001); Nodal, (Varlet et al., 1997), (Shen, 2007).
	Figure S1. Control experiments testing the cer‐S and foxH1‐SID constructs employed in this study. (A,B) Relative expression levels of mix1 transcripts at s9 (A) and s10 (B) in cer‐S‐injected embryos and uninjected sibling controls, analyzed by RT‐qPCR. Values for each biological replicate are indicated by symbols. Cer‐S‐injected biological replicates were tested by the effect on the expression of mix1, a direct target of Nodal signaling (Charney et al., 2017). mix1 expression was significantly reduced (p<0.05, unpaired, two‐tailed t‐test) in cer‐S‐injected embryos compared to uninjected sibling controls, both at s9 (p=0.0003) and at s10 (p=0.0001). Only those biological replicates that showed mix1 expression reduced to less than 50% in relation to uninjected sibling controls were used for RT‐qPCR analysis of the other markers shown in this work. (C,D) Effects of cer‐S on the paraxial mesoderm marker myod1. Control neurula (C) showing myod1 expression, which was abolished or drastically reduced in cer‐S‐ injected siblings (D). (E‐G) Effects of foxh1‐SID on the expression of the pan‐mesodermal marker tbxt. (E) Control early gastrula (s10.5) showing tbxt expression throughout the involuting mesoderm, including the GO. (F,G) Sibling gastrula unilaterally injected with foxh1‐SID mRNA. The injected side is evidenced by the tracer’s red fluorescence (G). Foxh1‐SID decreased tbxt expression in 100% of the injected embryos (n=17, N=1), as expected. Embryos are shown in dorsal views and are siblings of those analyzed for chrd.1 expression in one of the experiments shown in Table 2.

Agius, Endodermal Nodal-related signals and mesoderm induction in Xenopus. 2000, Pubmed, Xenbase

Agius, Endodermal Nodal-related signals and mesoderm induction in Xenopus. 2000, Pubmed , Xenbase
Aguirre, An intact brachyury function is necessary to prevent spurious axial development in Xenopus laevis. 2013, Pubmed , Xenbase
Anderson, Chordin and noggin promote organizing centers of forebrain development in the mouse. 2002, Pubmed
Artinger, Interaction of goosecoid and brachyury in Xenopus mesoderm patterning. 1997, Pubmed , Xenbase
Bachiller, The organizer factors Chordin and Noggin are required for mouse forebrain development. 2000, Pubmed
Bauer, The cleavage stage origin of Spemann's Organizer: analysis of the movements of blastomere clones before and during gastrulation in Xenopus. 1994, Pubmed , Xenbase
Bayramov, The presence of Anf/Hesx1 homeobox gene in lampreys suggests that it could play an important role in emergence of telencephalon. 2016, Pubmed
Beddington, Axis development and early asymmetry in mammals. 1999, Pubmed
Bellefroid, X-MyT1, a Xenopus C2HC-type zinc finger protein with a regulatory function in neuronal differentiation. 1996, Pubmed , Xenbase
Blanco-Suarez, Astrocyte-Secreted Chordin-like 1 Drives Synapse Maturation and Limits Plasticity by Increasing Synaptic GluA2 AMPA Receptors. 2018, Pubmed
Bouwmeester, Cerberus is a head-inducing secreted factor expressed in the anterior endoderm of Spemann's organizer. 1996, Pubmed , Xenbase
Branam, Zebrafish chordin-like and chordin are functionally redundant in regulating patterning of the dorsoventral axis. 2010, Pubmed
Camus, Absence of Nodal signaling promotes precocious neural differentiation in the mouse embryo. 2006, Pubmed
Cao, POU-V factors antagonize maternal VegT activity and beta-Catenin signaling in Xenopus embryos. 2007, Pubmed , Xenbase
Chandra, Neurogenesin-1 differentially inhibits the osteoblastic differentiation by bone morphogenetic proteins in C2C12 cells. 2006, Pubmed
Charney, A gene regulatory program controlling early Xenopus mesendoderm formation: Network conservation and motifs. 2017, Pubmed , Xenbase
Chen, Smad4 and FAST-1 in the assembly of activin-responsive factor. 1997, Pubmed , Xenbase
Cho, Molecular nature of Spemann's organizer: the role of the Xenopus homeobox gene goosecoid. 1991, Pubmed , Xenbase
Coffinier, Neuralin-1 is a novel Chordin-related molecule expressed in the mouse neural plate. 2001, Pubmed , Xenbase
Conlon, A primary requirement for nodal in the formation and maintenance of the primitive streak in the mouse. 1994, Pubmed
De Robertis, Dorsal-ventral patterning and neural induction in Xenopus embryos. 2004, Pubmed , Xenbase
Ermakova, The homeodomain factor Xanf represses expression of genes in the presumptive rostral forebrain that specify more caudal brain regions. 2007, Pubmed , Xenbase
Ermakova, The homeobox gene, Xanf-1, can control both neural differentiation and patterning in the presumptive anterior neurectoderm of the Xenopus laevis embryo. 1999, Pubmed , Xenbase
Feldman, Zebrafish organizer development and germ-layer formation require nodal-related signals. 1998, Pubmed
Foley, Reconciling different models of forebrain induction and patterning: a dual role for the hypoblast. 2000, Pubmed
Franco, Functional association of retinoic acid and hedgehog signaling in Xenopus primary neurogenesis. 1999, Pubmed , Xenbase
Gritsman, The EGF-CFC protein one-eyed pinhead is essential for nodal signaling. 1999, Pubmed , Xenbase
Harata, Nucleotide receptor P2RY4 is required for head formation via induction and maintenance of head organizer in Xenopus laevis. 2019, Pubmed , Xenbase
Hill, TGF-beta signalling pathways in early Xenopus development. 2001, Pubmed , Xenbase
Hoodless, FoxH1 (Fast) functions to specify the anterior primitive streak in the mouse. 2001, Pubmed
Hopwood, MyoD expression in the forming somites is an early response to mesoderm induction in Xenopus embryos. 1989, Pubmed , Xenbase
Ishibashi, Expression of Siamois and Twin in the blastula Chordin/Noggin signaling center is required for brain formation in Xenopus laevis embryos. 2008, Pubmed , Xenbase
Izpisúa-Belmonte, The homeobox gene goosecoid and the origin of organizer cells in the early chick blastoderm. 1993, Pubmed , Xenbase
Joubin, Formation and maintenance of the organizer among the vertebrates. 2001, Pubmed
Kaneda, Gastrulation and pre-gastrulation morphogenesis, inductions, and gene expression: similarities and dissimilarities between urodelean and anuran embryos. 2012, Pubmed , Xenbase
Keller, Vital dye mapping of the gastrula and neurula of Xenopus laevis. I. Prospective areas and morphogenetic movements of the superficial layer. 1975, Pubmed , Xenbase
Keller, Vital dye mapping of the gastrula and neurula of Xenopus laevis. II. Prospective areas and morphogenetic movements of the deep layer. 1976, Pubmed , Xenbase
Kinder, The organizer of the mouse gastrula is composed of a dynamic population of progenitor cells for the axial mesoderm. 2001, Pubmed
Kishi, Requirement of Sox2-mediated signaling for differentiation of early Xenopus neuroectoderm. 2000, Pubmed , Xenbase
Kuroda, Neural induction in Xenopus: requirement for ectodermal and endomesodermal signals via Chordin, Noggin, beta-Catenin, and Cerberus. 2004, Pubmed , Xenbase
Kurth, Establishment of mesodermal gene expression patterns in early Xenopus embryos: the role of repression. 2005, Pubmed , Xenbase
Kwan, Xbra functions as a switch between cell migration and convergent extension in the Xenopus gastrula. 2003, Pubmed , Xenbase
Latinkic, Goosecoid and mix.1 repress Brachyury expression and are required for head formation in Xenopus. 1999, Pubmed , Xenbase
Lawson, Classification scheme for genes expressed during formation and progression of the avian primitive streak. 2001, Pubmed
Leibovich, ADMP controls the size of Spemann's organizer through a network of self-regulating expansion-restriction signals. 2018, Pubmed , Xenbase
Lemaire, Expression cloning of Siamois, a Xenopus homeobox gene expressed in dorsal-vegetal cells of blastulae and able to induce a complete secondary axis. 1995, Pubmed , Xenbase
Levine, Proposal of a model of mammalian neural induction. 2007, Pubmed
Luu, Control of gastrula cell motility by the Goosecoid/Mix.1/ Siamois network: basic patterns and paradoxical effects. 2008, Pubmed , Xenbase
Matsui, Induction of initial heart alpha-actin, smooth muscle alpha-actin, in chick pregastrula epiblast: the role of hypoblast and fibroblast growth factor-8. 2008, Pubmed
McMahon, Noggin-mediated antagonism of BMP signaling is required for growth and patterning of the neural tube and somite. 1998, Pubmed
Miller-Bertoglio, Differential regulation of chordin expression domains in mutant zebrafish. 1997, Pubmed , Xenbase
Müller, Direct action of the nodal-related signal cyclops in induction of sonic hedgehog in the ventral midline of the CNS. 2000, Pubmed
Murgan, FoxA4 favours notochord formation by inhibiting contiguous mesodermal fates and restricts anterior neural development in Xenopus embryos. 2014, Pubmed , Xenbase
Pfirrmann, Molecular mechanism of CHRDL1-mediated X-linked megalocornea in humans and in Xenopus model. 2015, Pubmed , Xenbase
Piccolo, The head inducer Cerberus is a multifunctional antagonist of Nodal, BMP and Wnt signals. 1999, Pubmed , Xenbase
Pizard, Whole-mount in situ hybridization and detection of RNAs in vertebrate embryos and isolated organs. 2004, Pubmed , Xenbase
Rebagliati, Zebrafish nodal-related genes are implicated in axial patterning and establishing left-right asymmetry. 1998, Pubmed , Xenbase
Reid, Transcriptional integration of Wnt and Nodal pathways in establishment of the Spemann organizer. 2012, Pubmed , Xenbase
Reid, FoxH1 mediates a Grg4 and Smad2 dependent transcriptional switch in Nodal signaling during Xenopus mesoderm development. 2016, Pubmed , Xenbase
Reversade, Depletion of Bmp2, Bmp4, Bmp7 and Spemann organizer signals induces massive brain formation in Xenopus embryos. 2005, Pubmed , Xenbase
Sakuta, Ventroptin: a BMP-4 antagonist expressed in a double-gradient pattern in the retina. 2001, Pubmed , Xenbase
Sasai, Xenopus chordin: a novel dorsalizing factor activated by organizer-specific homeobox genes. 1994, Pubmed , Xenbase
Schohl, Beta-catenin, MAPK and Smad signaling during early Xenopus development. 2002, Pubmed , Xenbase
Shen, Nodal signaling: developmental roles and regulation. 2007, Pubmed
Shook, Pattern and morphogenesis of presumptive superficial mesoderm in two closely related species, Xenopus laevis and Xenopus tropicalis. 2004, Pubmed , Xenbase
Sidi, Maternal induction of ventral fate by zebrafish radar. 2003, Pubmed
Smith, Expression of a Xenopus homolog of Brachyury (T) is an immediate-early response to mesoderm induction. 1991, Pubmed , Xenbase
Stern, The marginal zone and its contribution to the hypoblast and primitive streak of the chick embryo. 1990, Pubmed
Stern, Head-tail patterning of the vertebrate embryo: one, two or many unresolved problems? 2006, Pubmed
Streit, Chordin regulates primitive streak development and the stability of induced neural cells, but is not sufficient for neural induction in the chick embryo. 1998, Pubmed
Streit, Initiation of neural induction by FGF signalling before gastrulation. 2000, Pubmed
Sudou, Dynamic in vivo binding of transcription factors to cis-regulatory modules of cer and gsc in the stepwise formation of the Spemann-Mangold organizer. 2012, Pubmed , Xenbase
Sun, Small C-terminal Domain Phosphatase 3 Dephosphorylates the Linker Sites of Receptor-regulated Smads (R-Smads) to Ensure Transforming Growth Factor β (TGFβ)-mediated Germ Layer Induction in Xenopus Embryos. 2015, Pubmed , Xenbase
Takahashi, Two novel nodal-related genes initiate early inductive events in Xenopus Nieuwkoop center. 2000, Pubmed , Xenbase
Tam, Mouse embryonic chimeras: tools for studying mammalian development. 2003, Pubmed
Tam, The allocation of epiblast cells to the embryonic heart and other mesodermal lineages: the role of ingression and tissue movement during gastrulation. 1997, Pubmed
Tam, Mouse gastrulation: the formation of a mammalian body plan. 1997, Pubmed
Varlet, nodal expression in the primitive endoderm is required for specification of the anterior axis during mouse gastrulation. 1997, Pubmed
Vincent, Cell fate decisions within the mouse organizer are governed by graded Nodal signals. 2003, Pubmed
von Dassow, Induction of the Xenopus organizer: expression and regulation of Xnot, a novel FGF and activin-regulated homeo box gene. 1993, Pubmed , Xenbase
Watanabe, FAST-1 is a key maternal effector of mesoderm inducers in the early Xenopus embryo. 1999, Pubmed , Xenbase
Wessely, Neural induction in the absence of mesoderm: beta-catenin-dependent expression of secreted BMP antagonists at the blastula stage in Xenopus. 2001, Pubmed , Xenbase
Wilson, Early steps in the development of the forebrain. 2004, Pubmed
Yamaguti, Xenopus hairy2b specifies anterior prechordal mesoderm identity within Spemann's organizer. 2005, Pubmed , Xenbase
Yamamoto, The transcription factor FoxH1 (FAST) mediates Nodal signaling during anterior-posterior patterning and node formation in the mouse. 2001, Pubmed
Zorn, Anterior endomesoderm specification in Xenopus by Wnt/beta-catenin and TGF-beta signalling pathways. 1999, Pubmed , Xenbase