Characterization of Brachyury-downstream notochord genes in the Ciona intestinalis embryo

Kohji Hotta, Hiroki Takahashi, Tomomi Asakura, Banjo Saitoh, Naohito Takatori, Yutaka Satou, Nori Satoh

Research output: Contribution to journalArticlepeer-review

138 Citations (Scopus)


The notochord has two major roles during chordate embryogenesis, as a source of inductive signals for the patterning of neural tube and paraxial mesoderm and as a supportive organ of the larval tail. Despite the recent identification of mutations that affect the notochord development in vertebrate embryos, little is known about genes that are expressed in the differentiating notochord itself. In the urochordate ascidian Ciona intestinalis, Brachyury (Ci-Bra) plays a key role in notochord differentiation. In a previous study, we isolated cDNA clones for nearly 40 potential Ci-Bra target genes that are expressed in notochord cells (H. Takahashi et al., 1999, Genes Dev. 13, 1519-1523). Here we characterized 20 of them by determining the complete nucleotide sequences of the cDNAs. These genes encode a broad spectrum of divergent proteins associated with notochord formation and function. Two genes encode ascidian homologs of the Drosophila Prickle LIM domain proteins and another encodes the ERM protein, all 3 of which appear to be involved in the control of cytoskeletal architecture. In addition, genes for netrin, leprecan, cdc45, ATP:citrate lyase, ATP sulfurylase/APS kinase, protein tyrosine phosphatase, β4-galactosyltransferase, fibrinogen-like protein, divergent tropomyosin-like proteins, and Drosophila Pellino-like protein were identified. The observation of the netrin gene expression in the notochord may provide the first molecular evidence that the ascidian notochord is a source of signals as in vertebrates. In addition, the present information should be used to identify nonchordate deuterostome tissues homologous to the notochord as well as genes which are expressed in the notochord cells of vertebrate embryos. (C) 2000 Academic Press.

Original languageEnglish
Pages (from-to)69-80
Number of pages12
JournalDevelopmental Biology
Issue number1
Publication statusPublished - 2000 Aug 1
Externally publishedYes


  • Ascidians
  • Brachyury
  • Cdc45
  • Cell shape changes
  • Downstream genes
  • Leprecan
  • Netrin
  • Notochord
  • Prickle LIM domain protein

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology


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