...Jasmine Yang; Ashly Brown; Debra Ellisor; Erin Paul; Nellwyn Hagan; Mark Zervas Wnt1 -expressing progenitors generate midbrain dopamine (MbDA) and cerebellum (Cb) neurons in distinct temporal windows and from spatially discrete progenitor domains. It has been shown that Wnt1 and Lmx1a participate...

... of Wnt1, the posterior-ventral region of the embryo is severely altered during early gastrulation. Strikingly, at this time, nodal and its downstream target genes gsc and bra are expressed ectopically, extending posteriorly to the blastopore. They override the initial specification of posterior-ventral...

... of neurons does not seem to result from a defect in NCC specification as all the usual markers, with the exception of Msx1 , are expressed in the dorsal caudal-most NT as early as E4/HH24. However, Bmp4-Wnt1 signaling, which triggers trunk NCC delamination, is impaired in this region due to persistence...

... was performed as described ( Simeone, 1999 ; Puelles et al., 2006 ) with GFP, Msx1, Lmx1a probes, each corresponding to a PCR fragment of variable length between 300 bp and 500 bp or with Wnt1, En1, Otx1,Gbx2 and Fgf8 probes( Puelles et al., 2004 ). Immunohistochemistry was performed as previously...

...Alfonso Lavado; Oleg V. Lagutin; Guillermo Oliver The homeobox gene Six3 represses Wnt1 transcription. It is also required in the anterior neural plate for the development of the mammalian rostral forebrain. We have now determined that at the 15- to 17-somite stage, the prospective diencephalon...

...Lisa M. Galli; Tiffany L. Barnes; Stephanie S. Secrest; Tatsuhiko Kadowaki; Laura W. Burrus A long-term goal of developmental biology is to understand how morphogens establish gradients that promote proper tissue patterning. A number of reports describe the formation of the Wg (Wnt1) gradient...

... play a central role in the modulation of different brain functions and are associated with major neurological and psychiatric disorders. Despite the importance of these cells, the molecular mechanisms controlling their development are still poorly understood. The secreted glycoprotein Wnt1 is expressed...

... in the vertebrate hindbrain, but the role of these cells is not known. We have investigated the function of the Wnt1 signalling molecule that is expressed by boundary and roof plate cells in the zebrafish hindbrain. Knockdown of wnt1 or of tcf3b , a mediator of Wnt signalling, leads to ectopic expression...

... domain upon which the cerebellum fuses. Elimination or overgrowth of this isthmic domain in Wnt1 sw/sw and En1 +/Otx2lacZ mutant mice, respectively, impair cerebellar midline fusion. Because the isthmus-derived midline cerebellar domain displays a distinct expression pattern of genes involved in BMP...

.... Additionally, we observed ectopic expression of Wnt1 in the embryonic roofplate organizer region and dorsal telencephalon. To determine the phenotypic consequences of such Wnt1 misexpression, we deleted a putative EMX2 DNA-binding site from the Wnt1 enhancer and used this to misexpress Wnt1 in the developing...

...Eiji Matsunaga; Tatsuya Katahira; Harukazu Nakamura The isthmus is the organizing center for the tectum and cerebellum. Fgf8 and Wnt1 are secreted molecules expressed around the isthmus. The function of Fgf8 has been well analyzed, and now accepted as the most important organizing signal...

...Isabel Olivera-Martinez; Sylvain Missier; Sandrine Fraboulet; Jacques Thélu; Danielle Dhouailly The chick dorsal feather-forming dermis originates from the dorsomedial somite and its formation depends primarily on Wnt1 from the dorsal neural tube. We investigate further the origin...

[email protected] ) 18 9 2001 © 2001. 2001 Compartment Fgf8 Mid-hindbrain organizer Retinoic acid Wnt1 Mouse Fig. 6. Spatial relationship of the expression domains of mes-met genes in Otx2 hOtx1/hOtx1 embryos at E10.5. (A) The normal expression patterns of Wnt1 , Fgf8...

... expression domains positions the MHB. How the positional information is translated into activation of Pax2 , Wnt1 and Fgf8 expression during MHB establishment remains unclear. In zebrafish spiel ohne grenzen ( spg ) mutants, the MHB is not established, neither isthmus nor cerebellum form, the midbrain...

... Xenopus Frizzled Wnt Wnt1 Frizzled 3 Neural crest PDZ domain Dishevelled GIPC Wnt1 was first identified as an oncogene activated by provirus insertion ( Nusse and Varmus, 1992 ). Subsequently, Wnt1 was shown to be a member of a family of secreted glycoproteins (Wnts) that regulate cell...

... the role of β-catenin during brain morphogenesis, by specifically inactivating the β- catenin gene in the region of Wnt1 expression. To achieve this, mice with a conditional (‘floxed’) allele of β-catenin with required exons flanked by loxP recombination sequences were intercrossed with transgenic mice...

..., we found that Fgf8, Wnt1 and Pax5 do not require the En genes for initiation of expression, but do for their maintenance, and Pax6 expression is expanded caudally into the midbrain in the absence of EN function. Since E9.5 En1/2 double mutants lack the mid/hindbrain region, forebrain mutant explants...

..., maintains the expression of the secreted factor Wnt1. Our conclusions are substantiated by the following: (i) Lmx1b mRNA becomes localized to the isthmus immediately after Fgf8 initiation, (ii) Wnt1 expression is localized to the Lmx1b expression domain, but with slightly later kinetics, (iii) Fgf8 -soaked...

... to regulation at the level of mRNA translation or protein stability. In the embryonic neuroepithelium, Myf5 is transcribed in differentiated neurons after the expression of neural basic Helix-Loop-Helix transcription factors. The signalling molecules Wnt1 and Sonic hedgehog, implicated in the activation of Myf5...

..., the endogenous Ol-eng2, Pax2, Wnt1 and Fgf8 , which are essential components of the MHB genetic cascade, were ectopically expressed in this region. Therefore, we propose that Ol-eng2 induces de novo formation of an isthmus-like structure, which correlates with the development of ectopic midbrain structures...