Investigating Evolutionarily Conserved Molecular Mechanisms Controlling Gene Expression in the Notochord

  • Julie E. Maguire
  • Aakarsha Pandey
  • Yushi Wu
  • Anna Di GregorioEmail author
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 1029)


Ascidian embryos have been employed as model systems for studies of developmental biology for well over a century, owing to their desirable blend of experimental advantages, which include their rapid development, traceable cell lineage, and evolutionarily conserved morphogenetic movements. Two decades ago, the development of a streamlined electroporation method drastically reduced the time and cost of transgenic experiments, and, along with the elucidation of the complete genomic sequences of several ascidian species, propelled these simple chordates to the forefront of the model organisms available for studies of regulation of gene expression. Numerous ascidian sequences with tissue-specific enhancer activity were isolated and rapidly characterized through systematic in vivo experiments that would require several weeks in most other model systems. These cis-regulatory sequences include a large collection of notochord enhancers, which have been used to visualize notochord development in vivo, to generate mutant phenotypes, and to knock down genes of interest. Moreover, their detailed characterization has allowed the reconstruction of different branches of the notochord gene regulatory network. This chapter describes how the use of transgenic techniques has rendered the ascidian Ciona a competitive model organism for studies of notochord development, evolution, and gene regulation.


Ascidian Brachyury Ciona cis-Regulatory Module Electroporation Enhancer Notochord T-Box Tbx2/3 Transcription factor 



Base pair(s)


Complementary DNA


Chromatin immunoprecipitation


cis-regulatory module




fluorescence-activated cell sorting


Green fluorescent protein


Gene regulatory network


Notochord enhancer


Orphan binding site


prolyl 3-hydroxylase1


Short hairpin RNA



Thanks to all present and past laboratory members and collaborators. We are particularly indebted to Drs. Diana José-Edwards, Lavanya Katikala, Izumi Oda-Ishii, and Yale Passamaneck for their original microphotographs. Research in our laboratory is supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number R01GM100466.


  1. Adams RR, Tavares AA, Salzberg A, Bellen HJ, Glover DM (1998) Pavarotti encodes a kinesin-like protein required to organize the central spindle and contractile ring for cytokinesis. Genes Dev 12(10):1483–1494CrossRefPubMedPubMedCentralGoogle Scholar
  2. Alten L, Schuster-Gossler K, Eichenlaub MP, Wittbrodt B, Wittbrodt J, Gossler A (2012) A novel mammal-specific three partite enhancer element regulates node and notochord-specific Noto expression. PLoS One 7(10):e47785CrossRefPubMedPubMedCentralGoogle Scholar
  3. Ang SL, Rossant J (1994) HNF-3 beta is essential for node and notochord formation in mouse development. Cell 78:561–574CrossRefPubMedGoogle Scholar
  4. Anno C, Satou A, Fujiwara S (2006) Transcriptional regulation of ZicL in the Ciona intestinalis embryo. Dev Genes Evol 216(10):597–605CrossRefPubMedGoogle Scholar
  5. Bagheri-Fam S, Barrionuevo F, Dohrmann U, Günther T, Schüle R, Kemler R, Mallo M, Kanzler B, Scherer G (2006) Long-range upstream and downstream enhancers control distinct subsets of the complex spatiotemporal Sox9 expression pattern. Dev Biol 291(2):382–397CrossRefPubMedGoogle Scholar
  6. Capellini TD, Dunn MP, Passamaneck YJ, Selleri L, Di Gregorio A (2008) Conservation of notochord gene expression across chordates: insights from the Leprecan gene family. Genesis 46(11):683–696CrossRefPubMedPubMedCentralGoogle Scholar
  7. Casey ES, O'Reilly MA, Conlon FL, Smith JC (1998) The T-box transcription factor Brachyury regulates expression of eFGF through binding to a non-palindromic response element. Development 125(19):3887–3894PubMedGoogle Scholar
  8. Chiba S, Jiang D, Satoh N, Smith WC (2009) Brachyury null mutant-induced defects in juvenile ascidian endodermal organs. Development 136(1):35–39CrossRefPubMedGoogle Scholar
  9. Christiaen L, Davidson B, Kawashima T, Powell W, Nolla H, Vranizan K, Levine M (2008) The transcription/migration interface in heart precursors of Ciona intestinalis. Science 320(5881):1349–1352CrossRefPubMedGoogle Scholar
  10. Cleaver O, Krieg PA (2001) Notochord patterning of the endoderm. Dev Biol 234(1):1–12CrossRefPubMedGoogle Scholar
  11. Cloney RA (1964) Development of the ascidian notochord. Acta Embryol Morphol Exp 7:111–130Google Scholar
  12. Conklin EG (1905) The organization and cell-lineage of the ascidian egg. J Acad Nat Sci 13:1–119Google Scholar
  13. Corbo JC, Levine M, Zeller RW (1997) Characterization of a notochord-specific enhancer from the Brachyury promoter region of the ascidian, Ciona intestinalis. Development 124(3):589–602PubMedGoogle Scholar
  14. Corbo JC, Fujiwara S, Levine M, Di Gregorio A (1998) Suppressor of hairless activates brachyury expression in the Ciona embryo. Dev Biol 203(2):358–368CrossRefPubMedGoogle Scholar
  15. Dehal P, Satou Y, Campbell RK, Chapman J, Degnan B, De Tomaso A, Davidson B, Di Gregorio A et al (2002) The draft genome of Ciona intestinalis: insights into chordate and vertebrate origins. Science 298(5601):2157–2167CrossRefPubMedGoogle Scholar
  16. Delsuc F, Brinkmann H, Chourrout D, Philippe H (2006) Tunicates and not cephalochordates are the closest living relatives of vertebrates. Nature 439(7079):965–968CrossRefPubMedGoogle Scholar
  17. Denker E, Jiang D (2012) Ciona intestinalis notochord as a new model to investigate the cellular and molecular mechanisms of tubulogenesis. Semin Cell Dev Biol 23(3):308–319CrossRefPubMedGoogle Scholar
  18. Denker E, Bocina I, Jiang D (2013) Tubulogenesis in a simple cell cord requires the formation of bi-apical cells through two discrete par domains. Development 140(14):2985–2996CrossRefPubMedGoogle Scholar
  19. Denker E, Sehring IM, Dong B, Audisso J, Mathiesen B, Jiang D (2015) Regulation by a TGFβ-ROCK-actomyosin axis secures a non-linear lumen expansion that is essential for tubulogenesis. Development 142(9):1639–1650CrossRefPubMedGoogle Scholar
  20. Deschet K, Nakatani Y, Smith WC (2003) Generation of ci-Brachyury-GFP stable transgenic lines in the ascidian Ciona savignyi. Genesis 35(4):248–259CrossRefPubMedGoogle Scholar
  21. Di Gregorio A (2017) T-box genes and developmental gene regulatory networks in ascidians. Curr Top Dev Biol 122:55–91CrossRefPubMedGoogle Scholar
  22. Di Gregorio A, Levine M (1999) Regulation of Ci-tropomyosin-like, a Brachyury target gene in the ascidian, Ciona intestinalis. Development 126(24):5599–5609PubMedGoogle Scholar
  23. Di Gregorio A, Corbo JC, Levine M (2001) The regulation of forkhead/HNF-3beta expression in the Ciona embryo. Dev Biol 229(1):31–43CrossRefPubMedGoogle Scholar
  24. Di Gregorio A, Harland RM, Levine M, Casey ES (2002) Tail morphogenesis in the ascidian, Ciona intestinalis, requires cooperation between notochord and muscle. Dev Biol 244(2):385–395CrossRefPubMedGoogle Scholar
  25. Dong B, Deng W, Jiang D (2011) Distinct cytoskeleton populations and extensive crosstalk control Ciona notochord tubulogenesis. Development 138(8):1631–1641CrossRefPubMedGoogle Scholar
  26. Dunn MP, Di Gregorio A (2009) The evolutionarily conserved leprecan gene: its regulation by Brachyury and its role in the developing Ciona notochord. Dev Biol 328(2):561–574CrossRefPubMedPubMedCentralGoogle Scholar
  27. Evans AL, Faial T, Gilchrist MJ, Down T, Vallier L, Pedersen RA, Wardle FC, Smith JC (2012) Genomic targets of Brachyury (T) in differentiating mouse embryonic stem cells. PLoS One 7(3):e33346CrossRefPubMedPubMedCentralGoogle Scholar
  28. Farley EK, Olson KM, Zhang W, Rokhsar DS, Levine MS (2016) Syntax compensates for poor binding sites to encode tissue specificity of developmental enhancers. Proc Natl Acad Sci U S A 113(23):6508–6513CrossRefPubMedPubMedCentralGoogle Scholar
  29. Friedman JR, Kaestner KH (2006) The Foxa family of transcription factors in development and metabolism. Cell Mol Life Sci 63(19–20):2317–2328CrossRefPubMedGoogle Scholar
  30. Gluecksohn-Schoenheimer S (1940) The effect of an early lethal (t) in the house mouse. Genetics 25(4):391–400PubMedPubMedCentralGoogle Scholar
  31. Hikosaka A, Kusakabe T, Satoh N, Makabe KW (1992) Introduction and expression of recombinant genes in ascidian embryos. Develop Growth Differ 34:631–638CrossRefGoogle Scholar
  32. Hikosaka A, Kusakabe T, Satoh N (1994) Short upstream sequences associated with the muscle-specific expression of an actin gene in ascidian embryos. Dev Biol 166:763–769CrossRefPubMedGoogle Scholar
  33. Holland LZ, Laudet V, Schubert M (2004) The chordate amphioxus: an emerging model organism for developmental biology. Cell Mol Life Sci 61(18):2290–2308CrossRefPubMedGoogle Scholar
  34. Hotta K, Takahashi H, Erives A, Levine M, Satoh N (1999) Temporal expression patterns of 39 Brachyury-downstream genes associated with notochord formation in the Ciona intestinalis embryo. Develop Growth Differ 41(6):657–664CrossRefGoogle Scholar
  35. Hotta K, Takahashi H, Asakura T, Saitoh B, Takatori N, Satou Y, Satoh N (2000) Characterization of Brachyury-downstream notochord genes in the Ciona intestinalis embryo. Dev Biol 224(1):69–80CrossRefPubMedGoogle Scholar
  36. Hotta K, Mitsuhara K, Takahashi H, Inaba K, Oka K, Gojobori T, Ikeo K (2007a) A web-based interactive developmental table for the ascidian Ciona intestinalis, including 3D real-image embryo reconstructions: I. From fertilized egg to hatching larva. Dev Dyn 236(7):1790–1805CrossRefPubMedGoogle Scholar
  37. Hotta K, Yamada S, Ueno N, Satoh N, Takahashi H (2007b) Brachyury-downstream notochord genes and convergent extension in Ciona intestinalis embryos. Develop Growth Differ 49(5):373–382CrossRefGoogle Scholar
  38. Hotta K, Takahashi H, Satoh N, Gojobori T (2008) Brachyury-downstream gene sets in a chordate, Ciona intestinalis: integrating notochord specification, morphogenesis and chordate evolution. Evol Dev 10(1):37–51CrossRefPubMedGoogle Scholar
  39. Imai KS, Hino K, Yagi K, Satoh N, Satou Y (2004) Gene expression profiles of transcription factors and signaling molecules in the ascidian embryo: towards a comprehensive understanding of gene networks. Development 131(16):4047–4058CrossRefPubMedGoogle Scholar
  40. Imai KS, Levine M, Satoh N, Satou Y (2006) Regulatory blueprint for a chordate embryo. Science 312(5777):1183–1187CrossRefPubMedGoogle Scholar
  41. Irvine SQ (2013) Study of cis-regulatory elements in the Ascidian Ciona intestinalis. Curr Genomics 14(1):56–67PubMedPubMedCentralGoogle Scholar
  42. Jeffery WR, Ewing N, Machula J, Olsen CL, Swalla BJ (1998) Cytoskeletal actin genes function downstream of HNF-3beta in ascidian notochord development. Int J Dev Biol 42(8):1085–1092PubMedGoogle Scholar
  43. Jeong Y, Epstein DJ (2003) Distinct regulators of Shh transcription in the floor plate and notochord indicate separate origins for these tissues in the mouse node. Development 130(16):3891–3902CrossRefPubMedGoogle Scholar
  44. Jiang D, Smith WC (2007) Ascidian notochord morphogenesis. Dev Dyn 236(7):1748–1757CrossRefPubMedPubMedCentralGoogle Scholar
  45. Jiang D, Munro EM, Smith WC (2005) Ascidian prickle regulates both mediolateral and anterior-posterior cell polarity of notochord cells. Curr Biol 15(1):79–85CrossRefPubMedGoogle Scholar
  46. José-Edwards DS, Kerner P, Kugler JE, Deng W, Jiang D, Di Gregorio A (2011) The identification of transcription factors expressed in the notochord of Ciona intestinalis adds new potential players to the brachyury gene regulatory network. Dev Dyn 240(7):1793–1805CrossRefPubMedPubMedCentralGoogle Scholar
  47. José-Edwards DS, Oda-Ishii I, Nibu Y, Di Gregorio A (2013) Tbx2/3 is an essential mediator within the Brachyury gene network during Ciona notochord development. Development 140(11):2422–2433CrossRefPubMedPubMedCentralGoogle Scholar
  48. José-Edwards DS, Oda-Ishii I, Kugler JE, Passamaneck YJ, Katikala L, Nibu Y, Di Gregorio A (2015) Brachyury, Foxa2 and the cis-Regulatory Origins of the Notochord. PLoS Genet 11(12):e1005730Google Scholar
  49. Katikala L, Aihara H, Passamaneck YJ, Gazdoiu S, José-Edwards DS, Kugler JE, Oda-Ishii I, Imai JH, Nibu Y, Di Gregorio A (2013) Functional Brachyury binding sites establish a temporal read-out of gene expression in the Ciona notochord. PLoS Biol 11(10):e1001697CrossRefPubMedPubMedCentralGoogle Scholar
  50. Kispert A, Koschorz B, Herrmann BG (1995) The T protein encoded by Brachyury is a tissue-specific transcription factor. EMBO J 14(19):4763–4772PubMedPubMedCentralGoogle Scholar
  51. Kubo A, Suzuki N, Yuan X, Nakai K, Satoh N, Imai KS, Satou Y (2010) Genomic cis-regulatory networks in the early Ciona intestinalis embryo. Development 137(10):1613–1623CrossRefPubMedGoogle Scholar
  52. Kumano G, Yamaguchi S, Nishida H (2006) Overlapping expression of FoxA and Zic confers responsiveness to FGF signaling to specify notochord in ascidian embryos. Dev Biol 300(2):770–784CrossRefPubMedGoogle Scholar
  53. Lacalli T (2012) The Middle Cambrian fossil Pikaia and the evolution of chordate swimming. Evodevo 3(1):12Google Scholar
  54. Lawson L, Harfe BD (2015) Notochord to nucleus pulposus transition. Curr Osteoporos Rep 13(5):336–341CrossRefPubMedGoogle Scholar
  55. Lemaire P (2009) Unfolding a chordate developmental program, one cell at a time: invariant cell lineages, short-range inductions and evolutionary plasticity in ascidians. Dev Biol 332(1):48–60CrossRefPubMedGoogle Scholar
  56. Levine M (2010) Transcriptional enhancers in animal development and evolution. Curr Biol 20(17):R754–R763CrossRefPubMedPubMedCentralGoogle Scholar
  57. Liu GH, Mao CZ, Wu HY, Zhou DC, Xia JB, Kim SK, Cai DQ, Zhao H, Qi XF (2016) Expression profile of rrbp1 genes during embryonic development and in adult tissues of Xenopus laevis. Gene Expr Patterns 23–24:1–6PubMedGoogle Scholar
  58. Mallatt J, Holland N (2013) Pikaia gracilens Walcott: stem chordate, or already specialized in the Cambrian? J Exp Zool B Mol Dev Evol 320:247–271CrossRefPubMedGoogle Scholar
  59. Matsumoto J, Kumano G, Nishida H (2007) Direct activation by Ets and Zic is required for initial expression of the Brachyury gene in the ascidian notochord. Dev Biol 306(2):870–882CrossRefPubMedGoogle Scholar
  60. Miyamoto DM, Crowther RJ (1985) Formation of the notochord in living ascidian embryos. J Embryol Exp Morphol 86:1–17PubMedGoogle Scholar
  61. Morris SC, Caron JB (2012) Pikaia gracilens Walcott, a stem-group chordate from the middle Cambrian of British Columbia. Biol Rev Camb Philos Soc 87:480–512CrossRefPubMedGoogle Scholar
  62. Müller F, Chang B, Albert S, Fischer N, Tora L, Strähle U (1999) Intronic enhancers control expression of zebrafish sonic hedgehog in floor plate and notochord. Development 126(10):2103–2116PubMedGoogle Scholar
  63. Myllyharju J, Kivirikko KI (1997) Characterization of the iron- and 2-oxoglutarate-binding sites of human prolyl 4-hydroxylase. EMBO J 16(6):1173–1180CrossRefPubMedPubMedCentralGoogle Scholar
  64. Newman-Smith E, Kourakis MJ, Reeves W, Veeman M, Smith WC (2015) Reciprocal and dynamic polarization of planar cell polarity core components and myosin. Elife 13(4):e05361Google Scholar
  65. Nibu Y, José-Edwards DS, Di Gregorio A (2013) From notochord formation to hereditary chordoma: the many roles of Brachyury. Biomed Res Int 2013:826435CrossRefPubMedPubMedCentralGoogle Scholar
  66. Nishida H, Satoh N (1983) Cell lineage analysis in ascidian embryos by intracellular injection of a tracer enzyme. I. Up to the eight-cell stage. Dev Biol 99:382–394CrossRefPubMedGoogle Scholar
  67. Nishida H, Satoh N (1985) Cell lineage analysis in ascidian embryos by intracellular injection of a tracer enzyme. II. The 16- and 32-cell stages. Dev Biol 110:440–454CrossRefPubMedGoogle Scholar
  68. Nishiyama A, Fujiwara S (2008) RNA interference by expressing short hairpin RNA in the Ciona intestinalis embryo. Develop Growth Differ 50(6):521–529CrossRefGoogle Scholar
  69. Oda-Ishii I, Di Gregorio A (2007) Lineage-independent mosaic expression and regulation of the Ciona multidom gene in the ancestral notochord. Dev Dyn 236(7):1806–1819CrossRefPubMedGoogle Scholar
  70. Olsen CL, Jeffery WR (1997) A forkhead gene related to HNF-3beta is required for gastrulation and axis formation in the ascidian embryo. Development 124(18):3609–3619PubMedGoogle Scholar
  71. Ortolani G (1954) Risultati definitive sulla distribuzione dei territory presuntivi degli organi nel germe di Ascidie allo stadio VIII, determinati con le marche al carbone. Pubbl Staz Zool Napoli 25:161–187Google Scholar
  72. Passamaneck YJ, Di Gregorio A (2005) Ciona intestinalis: chordate development made simple. Dev Dyn 233(1):1–19CrossRefPubMedGoogle Scholar
  73. Passamaneck YJ, Katikala L, Perrone L, Dunn MP, Oda-Ishii I, Di Gregorio A (2009) Direct activation of a notochord cis-regulatory module by Brachyury and FoxA in the ascidian Ciona intestinalis. Development 136(21):3679–3689CrossRefPubMedPubMedCentralGoogle Scholar
  74. Rastegar S, Hess I, Dickmeis T, Nicod JC, Ertzer R, Hadzhiev Y, Thies WG, Scherer G, Strähle U (2008) The words of the regulatory code are arranged in a variable manner in highly conserved enhancers. Dev Biol 318(2):366–377CrossRefPubMedGoogle Scholar
  75. Reese DE, Hall CE, Mikawa T (2004) Negative regulation of midline vascular development by the notochord. Dev Cell 6(5):699–708CrossRefPubMedGoogle Scholar
  76. Reverberi G (1971) Ascidians. In: Reverberi G (ed) Experimental embryology of marine and fresh-water invertebrates. North-Holland, Amsterdam, pp 507–550Google Scholar
  77. Rhee JM, Oda-Ishii I, Passamaneck YJ, Hadjantonakis AK, Di Gregorio A (2005) Live imaging and morphometric analysis of embryonic development in the ascidian Ciona intestinalis. Genesis 43(3):136–147CrossRefPubMedGoogle Scholar
  78. Sasaki H, Hogan BL (1993) Differential expression of multiple fork head related genes during gastrulation and axial pattern formation in the mouse embryo. Development 118(1):47–59PubMedGoogle Scholar
  79. Sasaki H, Yoshida K, Hozumi A, Sasakura Y (2014) CRISPR/Cas9-mediated gene knockout in the ascidian Ciona intestinalis. Develop Growth Differ 56(7):499–510CrossRefGoogle Scholar
  80. Sasakura Y, Suzuki MM, Hozumi A, Inaba K, Satoh N (2010) Maternal factor-mediated epigenetic gene silencing in the ascidian Ciona intestinalis. Mol Gen Genomics 283(1):99–110CrossRefGoogle Scholar
  81. Satoh N, Tagawa K, Takahashi H (2012) How was the notochord born? Evol Dev 14(1):56–75CrossRefPubMedGoogle Scholar
  82. Sawada A, Nishizaki Y, Sato H, Yada Y, Nakayama R et al (2005) Tead proteins activate the Foxa2 enhancer in the node in cooperation with a second factor. Development 132:4719–4729CrossRefPubMedGoogle Scholar
  83. Segade F, Cota C, Famiglietti A, Cha A, Davidson B (2016) Fibronectin contributes to notochord intercalation in the invertebrate chordate, Ciona intestinalis. EvoDevo 7(1):21CrossRefPubMedPubMedCentralGoogle Scholar
  84. Sehring IM, Dong B, Denker E, Bhattachan P, Deng W, Mathiesen BT, Jiang D (2014) An equatorial contractile mechanism drives cell elongation but not cell division. PLoS Biol 12(2):e1001781CrossRefPubMedPubMedCentralGoogle Scholar
  85. Sehring IM, Recho P, Denker E, Kourakis M, Mathiesen B, Hannezo E, Dong B, Jiang D (2015) Assembly and positioning of actomyosin rings by contractility and planar cell polarity. Elife 21(4):e09206Google Scholar
  86. Smith J (1999) T-box genes: what they do and how they do it. Trends Genet 15(4):154–158CrossRefPubMedGoogle Scholar
  87. Søviknes AM, Glover JC (2008) Continued growth and cell proliferation into adulthood in the notochord of the appendicularian Oikopleura dioica. Biol Bull 214(1):17–28CrossRefPubMedGoogle Scholar
  88. Stemple DL (2005) Structure and function of the notochord: an essential organ for chordate development. Development 132:2503–2512CrossRefPubMedGoogle Scholar
  89. Stolfi A, Christiaen L (2012) Genetic and genomic toolbox of the chordate Ciona intestinalis. Genetics 192(1):55–66CrossRefPubMedPubMedCentralGoogle Scholar
  90. Stolfi A, Gandhi S, Salek F, Christiaen L (2014) Tissue-specific genome editing in Ciona embryos by CRISPR/Cas9. Development 141(21):4115–4120CrossRefPubMedPubMedCentralGoogle Scholar
  91. Tada M, Casey ES, Fairclough L, Smith JC (1998) Bix1, a direct target of Xenopus T-box genes, causes formation of ventral mesoderm and endoderm. Development 125(20):3997–4006PubMedGoogle Scholar
  92. Takada N, Satoh N, Swalla BJ (2002) Expression of Tbx6, a muscle lineage T-box gene, in the tailless embryo of the ascidian Molgula tectiformis. Dev Genes Evol 212:354–356CrossRefPubMedGoogle Scholar
  93. Takahashi H, Hotta K, Erives A, Di Gregorio A, Zeller RW, Levine M, Satoh N (1999) Brachyury downstream notochord differentiation in the ascidian embryo. Genes Dev 13(12):1519–1523CrossRefPubMedPubMedCentralGoogle Scholar
  94. Takahashi H, Hotta K, Takagi C, Ueno N, Satoh N, Shoguchi E (2010) Regulation of notochord-specific expression of Ci-Bra downstream genes in Ciona intestinalis embryos. Zool Sci 27(2):110–118CrossRefPubMedGoogle Scholar
  95. Tamplin OJ, Cox BJ, Rossant J (2011) Integrated microarray and ChIP analysis identifies multiple Foxa2 dependent target genes in the notochord. Dev Biol 360(2):415–425CrossRefPubMedGoogle Scholar
  96. Thompson JM, Di Gregorio A (2015) Insulin-like genes in ascidians: findings in Ciona and hypotheses on the evolutionary origins of the pancreas. Genesis 53(1):82–104CrossRefPubMedGoogle Scholar
  97. Urry LA, Whittaker CA, Duquette M, Lawler J, DeSimone DW (1998) Thrombospondins in early Xenopus embryos: dynamic patterns of expression suggest diverse roles in nervous system, notochord, and muscle development. Dev Dyn 211:390–407CrossRefPubMedGoogle Scholar
  98. Veeman MT, Nakatani Y, Hendrickson C, Ericson V, Lin C, Smith WC (2008) Chongmague reveals an essential role for laminin-mediated boundary formation in chordate convergence and extension movements. Development 135(1):33–41CrossRefPubMedGoogle Scholar
  99. Wada H, Okuyama M, Satoh N, Zhang S (2006) Molecular evolution of fibrillar collagen in chordates, with implications for the evolution of vertebrate skeletons and chordate phylogeny. Evol Dev 8:370–377CrossRefPubMedGoogle Scholar
  100. Weisblat DA, Sawyer RT, Stent GS (1978) Cell lineage analysis by intracellular injection of a tracer enzyme. Science 202:1295–1298CrossRefPubMedGoogle Scholar
  101. Yagi K, Satou Y, Satoh N (2004) A zinc finger transcription factor, ZicL, is a direct activator of Brachyury in the notochord specification of Ciona intestinalis. Development 131(6):1279–1288CrossRefPubMedGoogle Scholar
  102. Yamada S, Ueno N, Satoh N, Takahashi H (2011) Ciona intestinalis Noto4 contains a phosphotyrosine interaction domain and is involved in the midline intercalation of notochord cells. Int J Dev Biol 55(1):11–18CrossRefPubMedGoogle Scholar
  103. Yasuo H, Satoh N (1993) Function of vertebrate T gene. Nature 364(6438):582–583CrossRefPubMedGoogle Scholar

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© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  • Julie E. Maguire
    • 1
  • Aakarsha Pandey
    • 1
  • Yushi Wu
    • 1
  • Anna Di Gregorio
    • 1
    Email author
  1. 1.Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA

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