Program in Genomics of Development, NICHD, NIH, Bethesda, Maryland, USA.
Dev Dyn. 2013 Sep;242(9):1033-42. doi: 10.1002/dvdy.23994. Epub 2013 Jun 27.
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.
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.
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.
斑马鱼的松果体（脑上体）是褪黑素产生的部位，含有光感受器细胞，并且作为昼夜节律起搏器发挥作用。由于它位于前脑的表面，因此易于操作，因此是分析松果体功能和发育的有用模型系统。我们之前分析了发育过程中的松果体转录组，结果表明许多基因在松果体中表现出高度动态的表达模式。
在优先在斑马鱼松果体中表达的基因中，我们鉴定了一个组织特异性形式的 unc119 基因家族，unc119c，它在胚胎到成年的所有检查阶段中都在白天和黑夜高度优先表达在松果体中。当 unc119c 的表达被抑制时，缰核连合（HC）的形成会受到特异性损害。Unc119c 的相互作用因子 Arl3l1 和 Arl3l2 以及 Wnt4a 也被证明对 HC 的形成是不可或缺的。
我们认为，Unc119c 与 Arl3l1/2 一起，在调节斑马鱼胚胎前脑 HC 形成过程中 Wnt4a 的产生和分泌中发挥重要作用。
