UNSW Embryo- Development of the Nervous System. Selected References Back to Neural Notes selected refs page 1 / page 2 Articles | Reviews | Books Links: Page 2 Page 1 PubMed Link About PubMed Note: A Selected List of References for Neural Development from PubMed March 1999. It was too difficult to keep neural development to one page so I have selected a few current Articles below and given a short description of the relevance to specific aspects of neural development. Internet access computers will be able to get abstract directly from PubMed (when available) by clicking Abstract below.

Articles Wnt Wnt signalling required for expansion of neural crest and CNS progenitors. Nature 1997 Oct 30;389(6654):966-70 Ikeya M, Lee SM, Johnson JE, McMahon AP, Takada S Centre for Molecular and Developmental Biology, Faculty of Science, Kyoto University, Japan. Interactions between cells help to elaborate pattern within the vertebrate central nervous system (CNS). The genes Wnt-1 and Wnt-3a, which encode members of the Wnt family of cysteine-rich secreted signals, are coexpressed at the dorsal midline of the developing neural tube, coincident with dorsal patterning. Each signal is essential for embryonic development, Wnt-1 for midbrain patterning, and Wnt-3a for formation of the paraxial mesoderm, but the absence of a dorsal neural-tube phenotype in each mutant suggests that Wnt signalling may be redundant. Here we demonstrate that in the absence of both Wnt- and Wnt-3a there is a marked deficiency in neural crest derivatives, which originate from the dorsal neural tube, and a pronounced reduction in dorsolateral neural precursors within the neural tube itself. These phenotypes do not seem to result from a disruption in the mechanisms responsible for establishing normal dorsoventral polarity. Rather, our results are consistent with a model in which local Wnt signalling regulates the expansion of dorsal neural precursors. Given the widespread expression of different Wnt genes in discrete areas of the mammalian neural tube, this may represent a general model for the action of Wnt signalling in the developing CNS. Dorsalization of the neural tube by the non-neural ectoderm. Dickinson ME, Selleck MA, McMahon AP, Bronner-Fraser M Development 1995 Jul;121(7):2099-106 The patterning of cell types along the dorsoventral axis of the spinal cord requires a complex set of inductive signals. While the chordamesoderm is a well-known source of ventralizing signals, relatively little is known about the cues that induce dorsal cell types, including neural crest. Here, we demonstrate that juxtaposition of the non-neural and neural ectoderm is sufficient to induce the expression of dorsal markers, Wnt-1, Wnt-3a and Slug, as well as the formation of neural crest cells. In addition, the competence of neural plate to express Wnt-1 and Wnt-3a appears to be stage dependent, occurring only when neural tissue is taken from stage 8-10 embryos but not from stage 4 embryos, regardless of the age of the non-neural ectoderm. In contrast to the induction of Wnt gene expression, neural crest cell formation and Slug expression can be induced when either stage 4 or stage 8-10 neural plates are placed in contact with the non-neural ectoderm. These data suggest that the non-neural ectoderm provides a signal (or signals) that specifies dorsal cell types within the neural tube, and that the response is dependent on the competence of the neural tissue. Identification of an evolutionarily conserved 110 base-pair cis-acting regulatory sequence that governs Wnt-1 expression in the murine neural plate. Development 1998 Jul;125(14):2735-46 Rowitch DH, Echelard Y, Danielian PS, Gellner K, Brenner S, McMahon AP The generation of anterior-posterior polarity in the vertebrate brain requires the establishment of regional domains of gene expression at early somite stages. Wnt-1 encodes a signal that is expressed in the developing midbrain and is essential for midbrain and anterior hindbrain development. Previous work identified a 5.5 kilobase region located downstream of the Wnt-1 coding sequence which is necessary and sufficient for Wnt-1 expression in vivo. Using a transgenic mouse reporter assay, we have now identified a 110 base pair regulatory sequence within the 5.5 kilobase enhancer, which is sufficient for expression of a lacZ reporter in the approximate Wnt-1 pattern at neural plate stages. Multimers of this element driving Wnt-1 expression can partially rescue the midbrain-hindbrain phenotype of Wnt-1(-/-) embryos. The possibility that this region represents an evolutionarily conserved regulatory module is suggested by the identification of a highly homologous region located downstream of the wnt-1 gene in the pufferfish (Fugu rubripes). These sequences are capable of appropriate temporal and spatial activation of a reporter gene in the embryonic mouse midbrain; although, later aspects of the Wnt-1 expression pattern are absent. Genetic evidence has implicated Pax transcription factors in the regulation of Wnt-1. Although Pax-2 binds to the 110 base pair murine regulatory element in vitro, the location of the binding sites could not be precisely established and mutation of two putative low affinity sites did not abolish activation of a Wnt-1 reporter transgene in vivo. Thus, it is unlikely that Pax proteins regulate Wnt-1 by direct interactions with this cis-acting regulatory region. Our analysis of the 110 base pair minimal regulatory element suggests that Wnt-1 regulation is complex, involving different regulatory interactions for activation and the later maintenance of transgene expression in the dorsal midbrain and ventral diencephalon, and at the midbrain-hindbrain junction. Other neural plate issues Establishment and maintenance of the border of the neural plate in the chick: involvement of FGF and BMP activity. Streit A, Stern CD Mech Dev 1999 Apr;82(1-2):51-66 Abstract | MH- A related issue about how the neural plate may be established and maintained. FGF = fibroblast growth factor BMP = bone morphogenic protein An early phase of embryonic Dlx5 expression defines the rostral boundary of the neural plate. Yang L, Zhang H, Hu G, Wang H, Abate-Shen C, Shen MM J Neurosci 1998 Oct 15;18(20):8322-30 Abstract | MH- A related issue about how the rostral end of the neural plate may be defined. Dlx = Distal-less, a homeobox gene Reviews   Books