Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
Int J Vitam Nutr Res. 2023 Feb;93(1):29-41. doi: 10.1024/0300-9831/a000705. Epub 2021 Apr 30.
Vitamin A is essential for a wide range of life processes throughout embryogenesis to adult life. With the aim of developing an model to monitor retinoic acid receptor (RAR) transactivation real-time in intact animals, we generated transgenic mice carrying a luciferase (luc) reporter gene under the control of retinoic acid response elements (RAREs) consisting of three copies of a direct repeat with five spacing nucleotides (DR5). : Transgenic mice carrying a RARE dependent luciferase reporter flanked with insulator sequence were generated by pronuclear injection. RARE dependent luciferase activity was detected by imaging or in tissue extracts following manipulations with RAR/retinoid X receptor (RXR) agonists, RAR antagonists or in vitamin A deficient mice. We found a strong induction of luciferase activity in a time and dose dependent manner by retinoic acid as well as RAR agonists, but not by the RXR agonist (using n=4-6 per group; 94 mice). In addition, luciferase activity was strongly reduced in vitamin A-deficient mice (n=6-9; 30 mice). These observations confirm that luciferase activity was controlled by RAR activation in the RARE-luc mouse. Luciferase activity was detectable in various organs, with high activity especially in brain and testis, indicating strong retinoid signalling in these tissues. The RARE-luc transgenic mice, which enabled real-time assessment of RAR activation, will be useful in understanding the normal physiology of vitamin A, the role of retinoid signalling in pathologies as well as to evaluate pharmacological ligands for RARs.
维生素 A 对于胚胎发生到成年期的广泛生命过程都是必不可少的。为了开发一种模型来实时监测完整动物体内视黄酸受体 (RAR) 的反式激活，我们生成了携带荧光素酶 (luc) 报告基因的转基因小鼠，该基因受包含三个直接重复五间隔核苷酸 (DR5) 的视黄酸反应元件 (RARE) 的控制。：通过原核注射生成侧翼带有绝缘子序列的 RARE 依赖性荧光素酶报告基因的转基因小鼠。通过 成像或在对 RAR/视黄醛 X 受体 (RXR) 激动剂、RAR 拮抗剂或维生素 A 缺乏的小鼠进行操作后，在组织提取物中检测 RARE 依赖性荧光素酶活性。我们发现视黄酸以及 RAR 激动剂以时间和剂量依赖的方式强烈诱导荧光素酶活性，但 RXR 激动剂则没有（每组 n=4-6；94 只小鼠）。此外，在维生素 A 缺乏的小鼠中（n=6-9；30 只小鼠），荧光素酶活性强烈降低。这些观察结果证实，荧光素酶活性受到 RARE-luc 小鼠中 RAR 激活的控制。荧光素酶活性可在各种器官中检测到，脑和睾丸中的活性特别高，表明这些组织中的视黄酸信号很强。能够实时评估 RAR 激活的 RARE-luc 转基因小鼠将有助于理解维生素 A 的正常生理学、视黄酸信号在病理学中的作用以及评估 RAR 的药理学配体。
