Habenular commissure formation in zebrafish is regulated by the pineal gland-specific gene unc119c

Dev Dyn. 2013 Sep;242(9):1033-42. doi: 10.1002/dvdy.23994. Epub 2013 Jun 27.


Background: The zebrafish pineal gland (epiphysis) is a site of melatonin production, contains photoreceptor cells, and functions as a circadian clock pacemaker. Since it is located on the surface of the forebrain, it is accessible for manipulation and, therefore, is a useful model system to analyze pineal gland function and development. We previously analyzed the pineal transcriptome during development and showed that many genes exhibit a highly dynamic expression pattern in the pineal gland.

Results: Among genes preferentially expressed in the zebrafish pineal gland, we identified a tissue-specific form of the unc119 gene family, unc119c, which is highly preferentially expressed in the pineal gland during day and night at all stages examined from embryo to adult. When expression of unc119c was inhibited, the formation of the habenular commissure (HC) was specifically compromised. The Unc119c interacting factors Arl3l1 and Arl3l2 as well as Wnt4a also proved indispensible for HC formation.

Conclusions: We suggest that Unc119c, together with Arl3l1/2, plays an important role in modulating Wnt4a production and secretion during HC formation in the forebrain of the zebrafish embryo.

Keywords: Zebrafish; epiphysis; habenular commissure; pineal gland; unc119; wnt4.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / biosynthesis*
  • Adaptor Proteins, Signal Transducing / genetics
  • Animal Structures / embryology*
  • Animals
  • Circadian Rhythm / physiology
  • Gene Expression Regulation, Developmental / physiology*
  • Organ Specificity / physiology
  • Pineal Gland / embryology*
  • Zebrafish / embryology*
  • Zebrafish / genetics
  • Zebrafish Proteins / biosynthesis*
  • Zebrafish Proteins / genetics


  • Adaptor Proteins, Signal Transducing
  • Zebrafish Proteins