Shi Zhuoyue, Wen Kailong, Zou Zhongyu, Fu Wenqin, Guo Kathryn, Sammudin Nabilah H, Ruan Xiangbin, Sullere Shivang, Wang Shuai, Zhang Xiaochang, Thinakaran Gopal, He Chuan, Zhuang Xiaoxi
The Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA.
Committee on Neurobiology, University of Chicago, Chicago, IL 60637, USA.
bioRxiv. 2024 Aug 9:2024.08.07.607063. doi: 10.1101/2024.08.07.607063.
Animals adapt to environmental challenges with long-term changes at the behavioral, circuit, cellular, and synaptic levels which often require new protein synthesis. The discovery of reversible N6-methyladenosine (mA) modifications of mRNA has revealed an important layer of post-transcriptional regulation which affects almost every phase of mRNA metabolism and therefore translational control. Many and studies have demonstrated the significant role of mA in cell differentiation and survival, but its role in adult neurons is understudied. We used cell-type specific gene deletion of , which encodes one of the subunits of the mA methyltransferase, and , which encodes one of the cytoplasmic mA reader proteins, in dopamine D1 receptor expressing or D2 receptor expressing neurons. or deficiency blunted responses to environmental challenges at the behavioral, cellular, and molecular levels. In three different behavioral paradigms, gene deletion of either or in D1 neurons impaired D1-dependent learning, whereas gene deletion of either or in D2 neurons impaired D2-dependent learning. At the cellular level, modulation of D1 and D2 neuron firing in response to changes in environments was blunted in all three behavioral paradigms in mutant mice. deletion resembled impairment caused by deletion in a cell type-specific manner, suggesting YTHDF1 is the main mediator of the functional consequences of mA mRNA methylation in the striatum. At the molecular level, while striatal neurons in control mice responded to elevated cAMP by increasing protein synthesis, striatal neurons in knockout mice didn't. Finally, boosting dopamine release by cocaine drastically increased YTHDF1 binding to many mRNA targets in the striatum, especially those that encode structural proteins, suggesting the initiation of long-term neuronal and/or synaptic structural changes. While the m6A-YTHDF1 pathway has similar functional significance at cellular level, its cell type specific deficiency in D1 and D2 neurons often resulted in contrasting behavioral phenotypes, allowing us to cleanly dissociate the opposing yet cooperative roles of D1 and D2 neurons.
动物通过行为、神经回路、细胞和突触水平的长期变化来适应环境挑战，而这些变化通常需要新的蛋白质合成。mRNA可逆的N6-甲基腺苷（m⁶A）修饰的发现揭示了转录后调控的一个重要层面，它几乎影响mRNA代谢的每个阶段，进而影响翻译控制。许多研究已经证明m⁶A在细胞分化和存活中具有重要作用，但其在成年神经元中的作用研究较少。我们在表达多巴胺D1受体或D2受体的神经元中，对编码m⁶A甲基转移酶亚基之一的 和编码细胞质m⁶A读取蛋白之一的 进行细胞类型特异性基因缺失。 或 缺乏会在行为、细胞和分子水平上减弱对环境挑战的反应。在三种不同的行为范式中，D1神经元中 或 的基因缺失会损害依赖D1的学习，而D2神经元中 或 的基因缺失会损害依赖D2的学习。在细胞水平上，在所有三种行为范式中，突变小鼠中D1和D2神经元对环境变化的放电调节均减弱。 缺失以细胞类型特异性方式类似于 缺失引起的损伤，表明YTHDF1是纹状体中m⁶A mRNA甲基化功能后果的主要介导者。在分子水平上，对照小鼠的纹状体神经元通过增加 蛋白合成来响应升高的cAMP，而 基因敲除小鼠的纹状体神经元则没有。最后，可卡因促进多巴胺释放会大幅增加YTHDF1与纹状体中许多mRNA靶标的结合，尤其是那些编码结构蛋白的靶标，这表明长期神经元和/或突触结构变化的启动。虽然m⁶A-YTHDF1途径在细胞水平上具有类似的功能意义，但其在D1和D2神经元中的细胞类型特异性缺陷通常会导致相反的行为表型，这使我们能够清楚地区分D1和D2神经元相反但协同的作用。
