Cloning and functional analysis of ascidian Mitf in vivo: Insights into the origin of vertebrate pigment cells

Ichiro Yajima, Kosuke Endo, Shigeru Sato, Reiko Toyoda, Hiroshi Wada, Shigeki Shibahara, Takaharu Numakunai, Kazuho Ikeo, Takashi Gojobori, Colin R. Goding, Hiroaki Yamamoto

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The microphthalmia-associated transcription factor (Mitf) is a basic-helix-loop-helix-leucine zipper (bHLH-ZIP) transcription factor essential for the development and function of all melanin-producing pigment cells in vertebrates. To elucidate the evolutionary history of Mitf and the antiquity of its association with pigment cells, we have isolated and characterized HrMitf, a sole member of the Mitf-TFE bHLH-ZIP subfamily in the ascidian Halocynthia roretzi. Maternal HrMitf mRNA is detected in the fertilized egg and in the animal hemisphere from 4-cell stage through the gastrula stage. From the neurula through the early tailbud stage, HrMitf is preferentially expressed in the pigment-lineage cells that express the lineage-specific melanogenesis genes tyrosinase (HrTyr) and Tyrp. Overexpression of HrMitf induced ectopic expression of HrTyr enzyme activity in mesenchymal cells where the same enzyme activity was induced by overexpression of HrPax3/7, suggesting that a part(s) of the Pax3-Mitf-tyrosinase gene regulatory cascade seen in vertebrate melanocytes is operative during ascidian embryogenesis. We also show HrMitf and mouse Mitf-A, a Mitf isoform abundantly expressed in pigmented epithelial cells, share similar functional characteristics. These results suggest antiquity of the association of the Mitf-TFE subfamily with pigment cells and may support the idea that acquisition of multiple promoters (isoforms) by an ancestral Mitf gene has allowed the evolution of multiple pigment cell types.

Original languageEnglish
Pages (from-to)1489-1504
Number of pages16
JournalMechanisms of Development
Volume120
Issue number12
DOIs
Publication statusPublished - 2003 Dec

Keywords

  • Ascidian
  • Eye
  • Microphthalmia
  • Mitf
  • Neural crest
  • Pax37
  • Pigment cells
  • Transcription factor
  • Tyrosinase
  • Tyrp

ASJC Scopus subject areas

  • Embryology
  • Developmental Biology

Fingerprint Dive into the research topics of 'Cloning and functional analysis of ascidian Mitf in vivo: Insights into the origin of vertebrate pigment cells'. Together they form a unique fingerprint.

  • Cite this

    Yajima, I., Endo, K., Sato, S., Toyoda, R., Wada, H., Shibahara, S., Numakunai, T., Ikeo, K., Gojobori, T., Goding, C. R., & Yamamoto, H. (2003). Cloning and functional analysis of ascidian Mitf in vivo: Insights into the origin of vertebrate pigment cells. Mechanisms of Development, 120(12), 1489-1504. https://doi.org/10.1016/j.mod.2003.08.009