Krug R G, Poshusta T L, Skuster K J, Berg M R, Gardner S L, Clark K J
Department of Biochemistry and Molecular Biology.
Mayo Graduate School, Mayo Clinic, Rochester, MN, USA.
Genes Brain Behav. 2014 Jun;13(5):478-87. doi: 10.1111/gbb.12135. Epub 2014 Apr 22.
Gene regulation resulting from glucocorticoid receptor and glucocorticoid response element interactions is a hallmark feature of stress response signaling. Imbalanced glucocorticoid production and glucocorticoid receptor activity have been linked to socioeconomically crippling neuropsychiatric disorders, and accordingly there is a need to develop in vivo models to help understand disease progression and management. Therefore, we developed the transgenic SR4G zebrafish reporter line with six glucocorticoid response elements used to promote expression of a short half-life green fluorescent protein following glucocorticoid receptor activation. Herein, we document the ability of this reporter line to respond to both chronic and acute exogenous glucocorticoid treatment. The green fluorescent protein expression in response to transgene activation was high in a variety of tissues including the brain, and provided single-cell resolution in the effected regions. The specificity of these responses is demonstrated using the partial agonist mifepristone and mutation of the glucocorticoid receptor. Importantly, the reporter line also modeled the temporal dynamics of endogenous stress response signaling, including the increased production of the glucocorticoid cortisol following hyperosmotic stress and the fluctuations of basal cortisol concentrations with the circadian rhythm. Taken together, these results characterize our newly developed reporter line for elucidating environmental or genetic modifiers of stress response signaling, which may provide insights to the neuronal mechanisms underlying neuropsychiatric disorders such as major depressive disorder.
由糖皮质激素受体与糖皮质激素反应元件相互作用所导致的基因调控是应激反应信号传导的一个标志性特征。糖皮质激素分泌失衡以及糖皮质激素受体活性异常与造成社会经济负担的神经精神疾病有关，因此有必要建立体内模型来帮助理解疾病的进展和治疗。为此，我们构建了转基因SR4G斑马鱼报告系，该报告系带有六个糖皮质激素反应元件，用于在糖皮质激素受体激活后促进半衰期较短的绿色荧光蛋白的表达。在此，我们记录了该报告系对慢性和急性外源性糖皮质激素治疗的反应能力。转基因激活后绿色荧光蛋白在包括脑在内的多种组织中表达量很高，并在受影响区域提供单细胞分辨率。使用部分激动剂米非司酮和糖皮质激素受体突变证明了这些反应的特异性。重要的是，该报告系还模拟了内源性应激反应信号传导的时间动态变化，包括高渗应激后糖皮质激素皮质醇分泌增加以及基础皮质醇浓度随昼夜节律的波动。综上所述，这些结果表征了我们新构建的报告系在阐明应激反应信号传导的环境或遗传修饰因子方面的作用，这可能为诸如重度抑郁症等神经精神疾病的神经元机制提供见解。
