Retinoic acid affects patterning along the anterior-posterior axis of the ascidian embryo

You Katsuyama, Hidetoshi Saiga

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Because retinoic acid (RA) is known to affect anterior-posterior patterning in vertebrate embryos, it was questioned whether it shows similar effects in a more primitive chordate, the ascidian Halocynthia roretzi. Ascidian embryos treated with RA exhibited truncated phenotypes in a dose- dependent manner similar to the anterior truncations seen in vertebrate embryos. The most severely affected larvae possessed a round trunk without the papillae characteristic of the anterior terminal epidermis. Retinoic acid also altered the expression of HrHox-1 and Hroth in a dose-dependent manner. Expression of HrHox-1 increased, whereas expression of Hroth decreased with increasing levels of RA. In treated embryos, HrHox-1 was first expressed pan- ectodermally, then degraded in all but specific regions of the embryo. By contrast, initiation of Hroth expression was not affected, but epidermal expression was lost while expression in the neural tube narrowed toward the anterior in tail-bud embryos. These alterations in the expression of homeobox genes appear to correlate closely to the morphological defects elicited by RA treatment, suggesting broad conservation of developmental patterning mechanisms within the Phylum Chordata.

Original languageEnglish
Pages (from-to)413-422
Number of pages10
JournalDevelopment Growth and Differentiation
Issue number4
Publication statusPublished - 1998
Externally publishedYes


  • Anterior-posterior patterning
  • Ascidian embryo
  • Homeobox genes
  • Retinoic acid

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology


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