Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA.
Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Neuron. 2020 Oct 14;108(1):111-127.e6. doi: 10.1016/j.neuron.2020.07.019. Epub 2020 Aug 13.
Cajal recognized that the elaborate shape of neurons is fundamental to their function in the brain. However, there are no simple and generalizable genetic methods to study neuronal or glial cell morphology in the mammalian brain. Here, we describe four mouse lines conferring Cre-dependent sparse cell labeling based on mononucleotide repeat frameshift (MORF) as a stochastic translational switch. Notably, the optimized MORF3 mice, with a membrane-bound multivalent immunoreporter, confer Cre-dependent sparse and bright labeling of thousands of neurons, astrocytes, or microglia in each brain, revealing their intricate morphologies. MORF3 mice are compatible with imaging in tissue-cleared thick brain sections and with immuno-EM. An analysis of 151 MORF3-labeled developing retinal horizontal cells reveals novel morphological cell clusters and axonal maturation patterns. Our study demonstrates a conceptually novel, simple, generalizable, and scalable mouse genetic solution to sparsely label and illuminate the morphology of genetically defined neurons and glia in the mammalian brain.
卡哈尔认识到神经元的精细形状是其在大脑中功能的基础。然而，目前还没有简单且可推广的遗传方法来研究哺乳动物大脑中的神经元或神经胶质细胞形态。在这里，我们描述了四种基于单核苷酸重复移码（MORF）的条件性稀疏细胞标记的小鼠品系，作为一种随机翻译开关。值得注意的是，经过优化的 MORF3 小鼠具有膜结合的多价免疫报告基因，可在每个大脑中实现数千个神经元、星形胶质细胞或小胶质细胞的 Cre 依赖性稀疏和明亮标记，揭示了它们复杂的形态。MORF3 小鼠与组织清除厚脑切片的成像以及免疫电镜兼容。对 151 个 MORF3 标记的发育中的视网膜水平细胞的分析揭示了新的形态细胞簇和轴突成熟模式。我们的研究证明了一种概念新颖、简单、可推广且可扩展的小鼠遗传解决方案，可稀疏标记和照亮哺乳动物大脑中遗传定义的神经元和神经胶质细胞的形态。
