Hinaux Hélène, Bachem Katharina, Battistara Margherita, Rossi Matteo, Xin Yaqun, Jaenichen Rita, Le Poul Yann, Arnoult Laurent, Kobler Johanna M, Grunwald Kadow Ilona C, Rodermund Lisa, Prud'homme Benjamin, Gompel Nicolas
Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany.
Aix-Marseille Université, CNRS, IBDM, Institut de Biologie du Développement de Marseille, Campus de Luminy Case 907, 13288 Marseille Cedex 9, France.
Dev Biol. 2018 Jun 15;438(2):111-123. doi: 10.1016/j.ydbio.2018.04.003. Epub 2018 Apr 7.
Pigmentation is a diverse and ecologically relevant trait in insects. Pigment formation has been studied extensively at the genetic and biochemical levels. The temporality of pigment formation during animal development, however, is more elusive. Here, we examine this temporality, focusing on yellow, a gene involved in the formation of black melanin. We generated a protein-tagged yellow allele in the fruit fly Drosophila melanogaster, which allowed us to precisely describe Yellow expression pattern at the tissue and cellular levels throughout development. We found Yellow expressed in the pupal epidermis in patterns prefiguring black pigmentation. We also found Yellow expressed in a few central neurons from the second larval instar to adult stages, including a subset of neurons adjacent to the clock neurons marked by the gene Pdf. We then specifically examined the dynamics of Yellow expression domain and subcellular localization in relationship to pigment formation. In particular, we showed how a late step of re-internalization is regulated by the large low-density lipoprotein receptor-related protein Megalin. Finally we suggest a new function for Yellow in the establishment of sharp pigmentation pattern boundaries, whereby this protein may assume a structural role, anchoring pigment deposits or pigmentation enzymes in the cuticle.
色素沉着是昆虫中一种多样且与生态相关的性状。色素形成已在基因和生化水平上得到广泛研究。然而，动物发育过程中色素形成的时间性却更难以捉摸。在此，我们研究这种时间性，重点关注黄色基因，它参与黑色黑色素的形成。我们在果蝇黑腹果蝇中产生了一个带有蛋白质标签的黄色等位基因，这使我们能够在整个发育过程中精确描述黄色基因在组织和细胞水平上的表达模式。我们发现黄色基因在蛹表皮中以预示黑色色素沉着的模式表达。我们还发现黄色基因在从幼虫第二龄期到成虫阶段的一些中枢神经元中表达，包括与由基因Pdf标记的时钟神经元相邻的一部分神经元。然后，我们特别研究了黄色基因表达域和亚细胞定位与色素形成相关的动态变化。特别是，我们展示了内化的后期步骤是如何由大型低密度脂蛋白受体相关蛋白巨膜蛋白调节的。最后，我们提出黄色基因在建立清晰的色素沉着模式边界方面具有新功能，即这种蛋白质可能发挥结构作用，将色素沉积物或色素沉着酶锚定在表皮中。
