Single-Cell Approaches to Reveal How Jumping Genes Individualize Neural Circuits

描述(申请人提供)：与个体中大多数健康细胞具有相同基因组的传统智慧相反，现在已知内源性L1反转录转座子在神经发生过程中“跳跃”并改变神经元基因组。独特基因组的多样性和流行率尚不清楚，但这些是了解移动元件介导的遗传多样性如何影响神经回路的基本数据。一个群体中的遗传多样性不能用大约一百万个细胞的典型批量分析来衡量；因此，我们建议开发单细胞方法来分析单个神经元基因组中的逆转录转座。为了了解新的移动元件插入的多样性和普遍性(即镶嵌成分)如何改变神经元功能，我们提出了三个实验。在一个实验中，我们将检查行为异常值中特定神经回路的马赛克组成。第二个实验将测试新的移动元素的加入是否会以不同的方式改变单个神经元的转录组。在第三个实验中，我们将产生很少或没有逆转座的小鼠系，以确定移动元件的插入对于神经元功能的特定方面是否既必要又充分。综上所述，应用单细胞基因组方法来理解神经元多样性有望挑战关于行为遗传学和人类神经发育障碍起源的基本假设。

DESCRIPTION (provided by applicant): Contrary to the conventional wisdom that the majority of healthy cells in an individual have identical genomes, endogenous L1 retrotransposons are now known to 'jump' during neurogenesis and change neuronal genomes. The diversity and prevalence of unique genomes is unknown, but these are essential data for understanding how mobile element-mediated genetic diversity affects neural circuits. Genetic diversity in a population cannot be measured using typical bulk analysis of a million or so cells; therefore, we propose to develop single cell methods to analyze retrotransposition in individual neuronal genomes. To understand how the diversity and prevalence (i.e. the mosaic composition) of de novo mobile element insertions alters neuron function, we propose three experiments. In one experiment, we will examine the mosaic composition of specific neural circuits in behavioral outliers. A second experiment will test the expectation that new mobile element insertions differentially alter the transcriptome of individual neurons. In a third experiment, we will generate mouse lines with little or no retrotransposition to determine if mobile element insertions are both necessary and sufficient for specific aspects of neuron function. Taken together, the application of single cell genomic approaches to understand neuronal diversity promises to challenge basic assumptions about the genetics of behavior and the origin of human neurodevelopmental disorders.