Basic Helix-Loop-Helix Proneural Genes and Neurogenesis in Xenopus Embryos

  • Eric Bellefroid
  • Jacob Souopgui


During vertebrate development, gastrulation establishes the three germ layers, ectoderm, mesoderm and endoderm, which characterize the triploblastic species. The ectoderm forms the outer layer and gives rise to the epidermis, the central nervous system (CNS), the peripheral nervous system (PNS), the placodes (nasal, lens, otic, and lateral line), and various glandular tissues. In Xenopus, the neurectoderm appears during gastrulation primarily as a consequence of the inhibition of bone morphogenetic proteins (BMPs) which act as epidermalizing agents. Inhibition occurs via the secretion of inhibitory signals from the organizer, that bind and antagonize the activity of BMPs, and also includes transcriptional repression of BMP gene expression (Munoz-Sanjuan and Brivanlou 2002). During neural development, the next important step is to define when and where neural precursors can exit the mitotic cell cycle. These differentiating progenitor cells produce either neurons or glia, the two major building blocks of the nervous system. This process takes place simultaneously with the progressive regionalization of the neural plate to give rise to postmitotic cells with distinct identities at different positions within the neurectoderm.


Notch Signaling Neuronal Differentiation Lateral Inhibition Neural Plate Xenopus Embryo 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Akamatsu W, Okano HJ, Osumi N, Inoue T, Nakamura S, Sakakibara S, Miura M, Matsuo N, Darnell RB, Okano H (1999) Mammalian ELAV-like neuronal RNA-binding proteins HuB and HuC promote neuronal development in both the central and the peripheral nervous systems. Proc Natl Acad Sci USA 96: 9885–9890PubMedCrossRefGoogle Scholar
  2. Antic D, Lu N, Keene JD (1999) ELAV tumor antigen, Hel-N1, increases translation of neurofilament M mRNA and induces formation of neurites in human teratocarcinoma cells. Genes Dev 13: 449–461.PubMedCrossRefGoogle Scholar
  3. Armisen R, Fuentes R, Olguin P, Cabrejos ME, Kukuljan M (2002) Repressor element-1 silencing transcription/neuron-restrictive silencer factor is required for neural sodium channel expression during development of Xenopus. J Neurosci. 222: 8347–8351Google Scholar
  4. Bagrodia S, Cerione RA (1999) Pak to the future. Trends Cell Biol 9: 350–355PubMedCrossRefGoogle Scholar
  5. Bao J, Talmage DA, Role LW, Gautier J (2000) Regulation of neurogenesis by interactions between HEN1 and neuronal LMO proteins. Development 127: 425–435PubMedGoogle Scholar
  6. Bellefroid, EJ, Bourguignon C, Holleman T, Ma Q, Anderson D, Kintner C, Pieler T (1996) XMyT1, a Xenopus C2HC-type zinc finger protein with a regulatory function in neuronal differentiation. Cell 87: 1191–1202PubMedCrossRefGoogle Scholar
  7. Bellefroid EJ, Kobbe A, Gruss P, Pieler T, Gurdon JB, Papalopulu N (1998) Xiro3 encodes a Xenop us homolog of the Drosophila Iroquois genes and functions in neural specification. EMBO J 17: 191–203PubMedCrossRefGoogle Scholar
  8. Bertrand N, Castro D, Guillemot F (2002) Proneural genes and the specification of neural cell types. Nat Rev Neurosci 3: 517–530PubMedCrossRefGoogle Scholar
  9. Blader P, Fischer N, Gradwohl G, Guillemot F, Strähle U (1997) The activity of Neurogenin 1 is controlled by local cues in the zebrafish embryo. Development 124: 4557–4569PubMedGoogle Scholar
  10. Brewster R, Lee J, Ruiz i Altaba A (1998) Gli/Zic factors pattern the neural plate by defining domains of cell differentiation. Nature 393: 579–583PubMedCrossRefGoogle Scholar
  11. Brown NL, Kanekar S, Vetter ML, Tucker PK, Gemza DL, Glaser T (1998) Math5 encodes a murine basic helix-loop-helix transcription factor expressed during early stages of retinal neurogenesis. Development 125: 4821–4833PubMedGoogle Scholar
  12. Brown NL, Patel S, Brezinski JA, Glaser T (2001) Math5 is required for retinal ganglion cell and optic nerve development. Development 128: 2497–2508PubMedGoogle Scholar
  13. Burns CJ, Vetter ML (2002) Xaths regulates neurogenesis in the Xenopus olfactory placodes. Dev Dynam 225: 536–543CrossRefGoogle Scholar
  14. Cao Y, Zhao H, Grunz H (2002) XETOR regulates the size of the proneural domain during primary neurogenesis in Xenopus laevis. Mech Dev 119: 1–35CrossRefGoogle Scholar
  15. Chalmers AD, Welchman D, Papalopulu N (2002) Intrinsic differences betwenn the superficial and deep layers of the Xenopus ectoderm control primary neuronal differentiation. Developmental Cell 2: 171–182PubMedCrossRefGoogle Scholar
  16. Chien C-T, Hsiao C-D, Jan LY, Jan YN (1996) Neuronal type information encoded in the basichelix-loop-helix domain of proneural genes. Proc Natl Acad Sci USA 93: 13239–13244PubMedCrossRefGoogle Scholar
  17. Chitnis A, Kintner C (1996) Sensitivity of proneural genes to lateral inhibition affects the pattern of primary neurons in Xenopus embryos. Development 122: 2295–2301PubMedGoogle Scholar
  18. Chitnis A, Henrique D, Lewis J, Ish-Horowicz D, Kintner C (1995) Primary neurogenesis in Xenopus embryos regulated by a homologue of the Drosophila neurogenic gene Delta. Nature 375: 761–766PubMedCrossRefGoogle Scholar
  19. Cornell RA, Eisen JS (2002) Delta/Notch signaling promotes formation of zebrafish neural crest by repressing Neurogenin 1 function. Development 129: 2639–2648PubMedGoogle Scholar
  20. Davis RL, Turner DL (2001) Vertebrate hairy and Enhancer of split related proteins: transcriptional repressors regulating cellular differentiation and embryonic patterning. Oncogene 20: 8342–8357PubMedCrossRefGoogle Scholar
  21. Deblandre GA, Wettstein DA, Koyano-Nakagawa N, Kintner C (1999) A two-step mechanism generates the spacing pattern of the ciliated cells in the skin of Xenopus embryos. Development 126, 4715–4728PubMedGoogle Scholar
  22. De la Calle-Mustienes EL, Glavic A, Modolell J, Gomez-Skarmeta J (2002) Xiro homeoproteins coordinate cell cycle exit and primary neuron formation by upregulating neuronal-fate repressors and downregulating the cell-cycle inhibitor XGadd45-gamma. Mech Dev 119: 69–80CrossRefGoogle Scholar
  23. Deschênes-Furry J, Belanger G, Perrone-Bizzozero N, Jasmin BJ(2003) Post-transcriptional regulation of acetylcholinesterase mRNAs in nerve growth factor-treated PC12 cells by the RNA-binding protein HuD. J Biol Chem 278: 5710–5717Google Scholar
  24. Dorsky RI, Rapaport, Harris WA (1995) Xotch inhibits cell differentiation in the Xenopus retina. Neuron 14: 487–496PubMedCrossRefGoogle Scholar
  25. Dubois L, Bally-Cuif L, Crozatier M, Moreau J, Paquereau L, Vincent A (1998) Xcoe2, a transcription factor of the Col/Olf-1/EBF family involved in the specification of primary neurons in Xenopus. Curr Biol 8: 199–209PubMedCrossRefGoogle Scholar
  26. Farah MH, Olson JM, Sucic HB, Hume RI, Tapscott SJ, Turner DL (2000) Generation of neurons by transient expression of neural bHLH proteins in mammalian cells. Development 127: 693–702PubMedGoogle Scholar
  27. Ferreiro B, Skoglund P, Bailey A, Dorsky R, Harris WA (1992) Xashl, a Xenopus homolog of achaete-scute: a proneural gene in anterior regions of the vertebrate CNS. Mech Dev 40: 25–36CrossRefGoogle Scholar
  28. Fode C, Gradwohl G, Morin X, Dierich A, LeMeur M, Goridis C, Guillemot F (1998) The bHLH protein NEUROGENIN 2 is a determination factor for epibranchial placode-derived sensory neurons. Neuron 20: 483–494PubMedCrossRefGoogle Scholar
  29. Forehand CJ, Farel PB (1982) Spinal cord development in anuran larvae. I. Primary and secondary neurons. J Comp Neurol 209: 395–408Google Scholar
  30. Franco PG, Paganelli A, Lopez SL, Carrasco AE (1999) Functional association of retinoic acid and hedgehog signaling in Xenopus primary neurogenesis. Development 126: 4257–4265PubMedGoogle Scholar
  31. Furukawa T, Mukherjee S, Bao ZZ, Morrow EM, Cepko CL (2000) rax, HES1, and Notchl promote the formation of Müller glia by postnatal retinal progenitor cells. Neuron 26: 383–394Google Scholar
  32. Gaiano N, Nye JS, Fishell G (2000) Radial glial identity is promoted by Notchl signaling in the murine forebrain. Neuron 26: 395–404PubMedCrossRefGoogle Scholar
  33. Ge W, Martinowich K, Wu X, He F, Miyamoto A, Fan G, Weinmaster G, Sun YE (2002) Notch signaling promotes astrogliogenesis via direct CSL-mediated glial gene activation. J Neurosci Res 69: 848–860PubMedCrossRefGoogle Scholar
  34. Gershon A, Rudnick J, Kalam L, Zimmerman K (2000) The homeodomain-containing gene Xdbx inhibits neuruonal differenciation in the developing embryo. Development 127: 2945–2954PubMedGoogle Scholar
  35. Gomez-Skarmeta JL, Glavic A, de la Calle-Mustienes E, Modolell J, Mayor R (1998) Xiro, a Xenopus homolog of the Drosophila Iroquois complex genes, controls development at the neural plate. EMBO J 17: 181–190Google Scholar
  36. Gomez-Skarmeta J, de La Calle-Mustienes E, Modolell J (2001) The Wnt-activated Xirol gene encodes a repressor that is essential for neural development and downregulates Bmp4. Development 128: 551–560Google Scholar
  37. Hardcastle Z, Papalopulu N (2000) Distinct effects of XBF-1 in regulating the cell cycle inhibitor p27x1c1 and imparting a neural fate. Development 127: 1303–1314PubMedGoogle Scholar
  38. Harris WA, Perron M (1998) Molecular recapitulation: the growth of the vertebrate retina. Int J Dev Biol 42: 299–304PubMedGoogle Scholar
  39. Hutcheson DA, Vetter ML (2001) The bHLH factors Xath5 and XNeuroD can upregulate the expression of XBrn3d, a POU-homeodomain transcription factor. Dev Biol 232: 327–338PubMedCrossRefGoogle Scholar
  40. Kanekar S, Perron M, Dorsky R, Harris WA, Jan LY, Vetter ML (1997) Xath5 participates in a network of bHLH genes in the developing Xenopus retina. Neuron 19: 981–994PubMedCrossRefGoogle Scholar
  41. Kim CH, Bae YK, Yamanaka Y, Yamashita S, Shimizu T, Fujii R, Park HC, Yeo SY, Huh TL, Hibi M, Hirano T (1997) Overexpression of neurogenin induces ectopic expression of HuC in zebrafish. Neurosci Lett 239: 113–116PubMedCrossRefGoogle Scholar
  42. Kim P, Helms AW, Johnson JE, Zimmerman K (1997) Xathl, a vertebrate homolog of Drosophila atonal, induces neuronal differentiation within ectodermal progenitors. Dev Biol 187: 1–12PubMedCrossRefGoogle Scholar
  43. Kintner C (2002) Neurogenesis in embryos and in adult neural stem cells. J Neurosci 22: 639–643PubMedGoogle Scholar
  44. Koyano-Nakagawa N, Wettstein D, Kintner C (1999) Activation of Xenopus genes required for lateral inhibition and neuronal differentiation during primary neurogenesis. Mol Cell Neurosci 14: 327–339PubMedCrossRefGoogle Scholar
  45. Koyano-Nakagawa N, Kim J, Anderson D, Kintner C (2000) Hes6 acts in a positive feedback loop with the neurogenins to promote neuronal diferentiation. Development 127: 4203–4216PubMedGoogle Scholar
  46. Lahaye K, Kricha S, Bellefroid EJ (2002) XNAP, a conserved ankyrin repeat-containing protein with a role in the Notch pathway during Xenopus primary neurogenesis. Mech Dev 110: 113–124PubMedCrossRefGoogle Scholar
  47. Lamar E, Kintner C, Goulding M (200la) Identification of NKL, a novel Gli-Kruppel zinc finger protein that promotes neuronal differentiation. Development 128: 1335–1346Google Scholar
  48. Lamar E, Deblandre G, Wettstein D, Gawantka V, Pollet N, Niehrs C, Kintner C (200 lb) Nrarp is a novel intracellular component of the Notch signaling pathway. Genes Dev 15: 1885–1899Google Scholar
  49. Lee JE, Hollenberg S, Snider L, Turner DL, Lipnick N, Weintraub H (1995) Conversion of Xenopus ectoderm into neurons by NeuroD, a basic helix-loop-helix protein. Science 268: 836–844PubMedCrossRefGoogle Scholar
  50. Lee J, Wu Y, Qi W, Xue H, Liu Y, Scheel D, German M, Qiu M, Guillemot F, Rao M (2003) Neurogenin3 participates in gliogenesis in the developing vertebrate spinal cord. Dev Biol 253: 8498CrossRefGoogle Scholar
  51. Lo L, Dormand E, Greenwood A, Anderson DJ (2002) Comparison of the generic neuronal differentiation and neuron subtype specification functions of mammalian achaete-scute and atonal homologs in cultures of neural progenitor cells. Development 129: 1553–1567PubMedGoogle Scholar
  52. Ma Q, Kintner C, Anderson DJ (1996) Identification of neurogenin, a vertebrate neuronal determination gene. Cell 87: 43–52PubMedCrossRefGoogle Scholar
  53. Ma Q, Chen Z, del Barco Barrantes I, de la Pompa JL, Anderson DJ (1998) Neurogeninl is essential for the determination of neuronal precursors for proximal cranial sensory ganglia. Neuron 20: 469–482PubMedCrossRefGoogle Scholar
  54. Marcus EA, Kintner C, Harris W (1998) The role of GSK3beta in regulating neuronal differentiation in Xenopus laevis. Mol Cell Neurosci 12: 269–280PubMedCrossRefGoogle Scholar
  55. Massari ME, Murre C (2000) Helix-loop-helix proteins: regulators of transcription in eucaryotic organisms. Mol Cell Biol 20: 429–440PubMedCrossRefGoogle Scholar
  56. Mizuseki K, Kishi M, Matsui M, Nakanishi S, Sasai Y (1998a) Xenopus Zic-related-1 and Sox-2, two factors induced by chordin, have distinct activities in the initiation of neural induction. Development 125: 579–587Google Scholar
  57. Mizuseki K, Kishi M, Shiota K, Nakanishi S, Sasai Y (1998b) SoxD: an essential mediator of induction of anterior neural tissues in Xenopus embryos. Neuron 21: 77–85PubMedCrossRefGoogle Scholar
  58. Moore KB, Schneider ML, Vetter M (2002) Posttranslational mechanisms control the timing of bHLH function and regulate retinal cell fate. Neuron 34: 183–195PubMedCrossRefGoogle Scholar
  59. Moreno TA, Bronner-Fraser M (2001) The secreted glycoprotein Noelin-1 promotes neurogenesis in Xenopus. Dev Biol 240: 340–360PubMedCrossRefGoogle Scholar
  60. Morrison SJ, Perez SE, Qiao Z, Verdi JM, Hicks C, Weinmaster G, Anderson DJ (2000) Transient Notch activation initiates an irreversible switch from neurogenesis to gliogenesis by neural crest stem cells. Cell 101: 499–510PubMedCrossRefGoogle Scholar
  61. Morrow EM, Furukawa T, Lee JE, Cepko CL (1999) NeuroD regulates multiple functions in the developing neural retina in rodent. Development 126: 126–136Google Scholar
  62. Mumm J, Kopan R (2000) Notch signaling: from the outside in. Dev Biol 228: 151–165PubMedCrossRefGoogle Scholar
  63. Munoz-Sanjuan I, Brivanlou AH (2002) Neural induction, the default model and embryonic stem cells. Nat Rev Neurosci 3: 271–280PubMedCrossRefGoogle Scholar
  64. Nieto M, Schurmans C, Britz O, Guillemot F (2001) Neural bHLH genes control the neuronal versus glial fate decision in cortical progenitors. Neuron 29: 401–413PubMedCrossRefGoogle Scholar
  65. Ohmuna S, Philpott A, Wang K, Holt CE, Harris WA (1999) p27Xicl, a Cdk inhibitor, promotes the determination of glial cells in Xenopus retina. Cell 99: 499–510Google Scholar
  66. Ohnuma S, Philpott A, Harris WA (2001) Cell-cycle and cell fate in the nervous system. Curr Opin Neurobiol 11: 66–73PubMedCrossRefGoogle Scholar
  67. Ohnuma S, Hopper S, Wang KC, Philpott A, Harris W (2002) Co-ordinating retinal histogenesis: early cell cycle exit enhances early cell fate determination in the Xenopus retina. Development 129: 2435–2446PubMedGoogle Scholar
  68. Olson EC, Schinder AF, Dantzker J, Marcus EA, Spitzer NC, Harris WA (1998) Properties of ectopic neurons induced by Xenopus neurogeninl misexpression. Mol Cell Neurosci 12: 281–299PubMedCrossRefGoogle Scholar
  69. Papalopulu N, Kintner C (1996) A posteriorising factor, retinoic acid, reveals that anteroposterior patterning controls the timing of neuronal differentiation in Xenopus neurectoderm. Development 122: 3409–3418PubMedGoogle Scholar
  70. Park HC, Kim CH, Bae YK, Yeo SY, Kim SH, Hong SK, Shin J, Yoo KW, Hibi M, Hirano T, Miki N, Chitnis AB, Huh TL (2000) Analysis of upstream elements in the HuC promoter leads to the establishment of transgenic zebrafish with fluorescent neurons. Dev Biol 227: 279–293PubMedCrossRefGoogle Scholar
  71. Perron M, Harris WA (1999) Cellular determination in amphibian retina. In: Moody SA (ed) Cell fate and cell lineage determination. Academic Press, San Diego, pp 353–368CrossRefGoogle Scholar
  72. Perron M, Harris WA (2000) Determination of veretebrate retinal progenitor cell fate by the Notch pathway and basic helix-loop-helix transcription factors. Cell Mol Life Sci 57: 215–223PubMedCrossRefGoogle Scholar
  73. Perron M, Kanekar S, Vetter M, Harris WA (1998) The genetic sequence of retinal development in the ciliary margin of the Xenopus eye. Dev Biol 199: 185–200PubMedCrossRefGoogle Scholar
  74. Perron M, Furrer M-P, Wegnez M, Theodore L (1999) Xenopus elav-like genes are differentially expressed during neurogenesis. Mech Dev 84: 139–142Google Scholar
  75. Perron M, Opdecamp K, Butler K, Harris WA, Bellefroid EJ (1999) X-ngnr-1 and Xath3 promote ectopic expression of sensory neuron markers in the neurula ectoderm and have distinct inducing properties in the retina. Proc Natl Acad Sci USA 96: 14996–15001PubMedCrossRefGoogle Scholar
  76. Perrone-Bizzozero N, Bolognani F (2002) Role of HuD and other RNA-binding proteins in neural development and plasticity. J Neurosci Res 68: 121–126PubMedCrossRefGoogle Scholar
  77. Pozzoli O, Bosetti A, Croci L, Consalez GG, Vetter M (2001) Xebf3 is a regulator of neuronal diferentiation during primary neurogenesis in Xenopus. Dev Biol 233: 495–512PubMedCrossRefGoogle Scholar
  78. Ramain P, Khechumian R, Arbogast N, Ackermann C, Heitzler P (2000) Interactions between chip and the achaete/scute-daughterless heterodimers are required for pannier-driven pro-neural patterning. Mol Cell 6: 781–790PubMedCrossRefGoogle Scholar
  79. Scheer N, Groth A, Hans S, Campos-Ortega JA (2001) An instructive function for Notch in promoting gliogenesis in the zebrafish retina. Development 128: 1099–1107PubMedGoogle Scholar
  80. Schlosser G, Koyano-Nakagawa N (2002) Thyroid hormone promotes neurogenesis in the Xenopus spinal cord. Developmental Dynamics 225: 485–498PubMedCrossRefGoogle Scholar
  81. Schneider ML, Turner DL, Vetter ML (2001). Notch signaling can inhibit Xath5 function in the neural plate and developing retina. Mol Cell Neurosci 18: 458–472PubMedCrossRefGoogle Scholar
  82. Schneider ML, Turner DL, Vetter ML (2001) Notch signalling can inhibit Xath5 function in the neural plate and developing retina. Mol Cell Neurosci 18: 458–472PubMedCrossRefGoogle Scholar
  83. Sharma A, Moore M, Marcora E, Lee JE, Qiu Y, Samaras S, Stein R (1999) The NeuroDl/Beta2 sequences essential for insulin gene transcription colocalize with those necessary for neurogenesis and p300/CREB binding protein binding. Mol Cell Biol 19: 704–713PubMedGoogle Scholar
  84. Sharpe C, Goldstone K (2000) Retinoid signalling acts during the gastrula stages to promote primary neurogenesis. Int J Dev Biol 44: 463–470PubMedGoogle Scholar
  85. Souopgui J, Solter M, Pieler T (2002) XPak3 promotes cell cycle withdrawal during primary neurogenesis in Xenopus laevis. EMBO J 21: 6429–6439PubMedCrossRefGoogle Scholar
  86. Sriuranpong V, Borges MW, Strock CL, Nakakura EK, Watkins DN, Blaumueller CM, Nelkin BD, Ball DW (2002) Notch signaling induces rapid degradation of achaete-scute homolog 1. Mol Cell Biol 22: 3129–3139PubMedCrossRefGoogle Scholar
  87. Sun Y, Nadal-Vicens M, Misono S, Lin MZ, Zubiaga A, Hua X, Fan G, Greenberg ME (2001) Neurogenin promotes neurogenesis and inhibits glial differentiation by independent mechanisms. Cell 104: 365–376PubMedCrossRefGoogle Scholar
  88. Taelman V, Opdecamp K, Avalosse B, Ryan K, Bellefroid EJ (2001) Xath2, a bHLH gene expressed during a late transition stage of neurogenesis in the forebrain of Xenopus embryos. Mech Dev 101: 199–202PubMedCrossRefGoogle Scholar
  89. Takebayashi T, Takahashi S, Yokota C, Tsuda H, Nakanishi S, Asashima M, Kageyama R (1997) Conversion of ectoderm into a neural fate by ATH-3, a vertebrate basic helix-loop-helix gene homologous to Drosophila proneural gene atonal. EMBO J 16: 384–395PubMedCrossRefGoogle Scholar
  90. Talikka M, Perez S, Zimmerman K (2002) Distinct patterns of downstream target activation are specified by the helix-loop-helix domain of proneural basic helix-loop-helix transcription factors. Dev Biol 247: 137–148PubMedCrossRefGoogle Scholar
  91. Tomita K, Moriyoshi K, Nakanishi S, Guillemot F, Kageyama R (2000) Mammalian achaete-scute and atonal homologs regulate neuronal versusglial fate determination in the central nervous system. EMBO J 19: 5460–5472PubMedCrossRefGoogle Scholar
  92. Turner DL, Weintraub H (1994) Expression of achaete-scute homolog 3 in Xenopus embryos converts ectodermal cells to a neural fate. Genes Dev 8: 1434–1447PubMedCrossRefGoogle Scholar
  93. Vernon AE, Devine C, Philpott A (2003) The cdk inhbibitor p27X1l is required for differentiation of primary neurones in Xenopus. Development 130: 85–92PubMedCrossRefGoogle Scholar
  94. Vetter M (2001) A turn of the helix: preventing the glia fate. Neuron 29: 559–562PubMedCrossRefGoogle Scholar
  95. Wang SW, Kim BS, Ding K, Wang H, Sun D, Johnson RL, Klein WH, Gan L (2001) Requirement for math5 in the development of retinal ganglion cells. Genes Dev 15: 24–29PubMedCrossRefGoogle Scholar
  96. Wang X, Kprzh V, Gong Z (2002) The functional specificity of NeuroD is defined by a single amino acid residue ( Nll) in the basic domain. FEBS Lett 520: 139–144Google Scholar
  97. Weintraub H (1993) The MyoD family and myogenesis: redundancy, networks and thresholds. Cell 75: 1241–1244PubMedCrossRefGoogle Scholar
  98. Wettstein DA, Turner DL, Kintner C (1997) The Xenopus homolog of Drosophila Suppressor of Hairless mediates Notch signaling during primary neurogenesis. Development 124: 693–702PubMedGoogle Scholar
  99. Zimmerman K, Shih J, Bars J, Collazo A, Anderson A, Anderson DJ (1993) Xash-3, a novel Xenopus achaete-scute homolog, provides an early marker of planar neural induction and position along the mediolateral axis of the neural plate. Development 119: 221–232PubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • Eric Bellefroid
    • 1
  • Jacob Souopgui
    • 2
    • 3
  1. 1.Laboratoire d’Embryologie Moléculaire, IBMMUniversité Libre de BruxellesGosseliesBelgium
  2. 2.Göttingen Zentrum für Molekulare BioscienceGeorg-August-Universität GöttingenGöttingenGermany
  3. 3.Department of Biochemistry, Faculty of ScienceUniversity of Yaounde IYaoundeCameroon

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