Yang Jing, O'Tousa Joseph E
Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
Mol Cell Neurosci. 2007 May;35(1):49-56. doi: 10.1016/j.mcn.2007.02.001. Epub 2007 Feb 8.
The Drosophila genes ninaB and ninaD, encoding a beta-carotene oxygenase and a type B scavenger receptor respectively, are essential for the biosynthesis of the 3-hydroxyretinal chromophore of rhodopsin. We analyzed transgenic reporter strains and performed in situ hybridization to show that both ninaB and ninaD are expressed in the adult brain but not retinal tissues. Developmental RT-PCR and tissue expression studies showed that ninaB is only expressed in the adult brain, while ninaD is expressed in the adult brain, the adult body, and many larval tissues. The data support a model in which NinaD is required for uptake and storage of dietary carotenoids throughout the larval and adult stages of development. Beta-carotene is transported to the adult brain, where cellular uptake by NinaD allows cleavage by the NinaB enzyme to produce retinal. Retinal is then transported to the retina for rhodopsin biogenesis.
果蝇基因ninaB和ninaD分别编码一种β-胡萝卜素加氧酶和一种B型清道夫受体，它们对于视紫红质的3-羟基视黄醛发色团的生物合成至关重要。我们分析了转基因报告菌株并进行了原位杂交，以表明ninaB和ninaD在成体大脑中表达，但不在视网膜组织中表达。发育性逆转录聚合酶链反应（RT-PCR）和组织表达研究表明，ninaB仅在成体大脑中表达，而ninaD在成体大脑、成体身体和许多幼虫组织中表达。这些数据支持了一个模型，即在整个幼虫和成虫发育阶段，NinaD是膳食类胡萝卜素摄取和储存所必需的。β-胡萝卜素被转运到成体大脑，在那里NinaD介导的细胞摄取使得NinaB酶能够切割产生视黄醛。然后视黄醛被转运到视网膜用于视紫红质的生物合成。
