Nature Neuroscience. For the first time, Yan Jun team analyzed the molecular mechanism of the circadian rhythm center.

The circadian rhythm of inature exists widely in organisms and plays an important role in regulating many physiological processes such as movement, sleep, metabolism and so on.it is believed that the circadian rhythm of mammals is controlled by the suprachiasmatic nucleus (SCN) in the brain.however, it is not clear about the overall cell type of SCN, the spatial distribution of different cell types in SCN, and how these cell types play a role in the circadian rhythm.on February 17, 2020, Yan Jun team from the center for excellence in brain science and intelligent technology of Chinese Academy of Sciences (Institute of Neuroscience), Shanghai brain science and brain like research center, and State Key Laboratory of neuroscience published an online report entitled "spatial single cell analysis of gene expression in the mouse suppressive" In this paper, we studied the distribution of monocytes in monocytes by three-dimensional sequencing The research on the neural mechanism of circadian rhythm in mammals has laid an important foundation.circadian rhythm exists widely in organisms and plays an important role in regulating many physiological processes such as exercise, sleep, metabolism and so on.it is believed that the circadian rhythm of mammals is controlled by the suprachiasmatic nucleus (SCN) in the brain.SCN can receive the light and dark signals from the retina, generate the circadian rhythm oscillation, and transmit the rhythm signal to the whole body.at the molecular level, circadian rhythm is generated by a series of transcription translation feedback loops (ttfl) composed of a series of core rhythm genes.previous studies have shown that the expression of core rhythm genes in SCN neurons shows synchronous oscillation, and cells in different spatial positions have different oscillation phases.studies have shown that SCN cells express a variety of neuropeptides and receptors, and their intercellular communication network is an important basis for synchronization of gene expression in SCN cells.previous studies on SCN only focused on the cells expressing VIP and AVP. However, it is not clear about the comprehensive cell types of SCN, the spatial distribution of different cell types in SCN, and how these cell types play a role in circadian rhythm.in this study, we systematically classified the cells in the suprachiasmatic nucleus (SCN), the circadian rhythm center of mice, by using single cell sequencing technology, and found new neuronal subtypes, revealing the differences of gene expression of these cell subtypes in the process of circadian rhythm and light stimulation. At the same time, the three-dimensional spatial distribution of each subtype cell was completely reconstructed at the single cell level The neural mechanism of circadian rhythm in animals has laid an important foundation.in this study, drop SEQ, single molecule fluorescence in situ hybridization (smfish) and laser microdissection sequencing (LCM SEQ) were used to analyze mouse SCN samples collected at different time points of day and night. The transcriptome was used to systematically classify the SCN cells and obtain the gene expression rhythm in different cell types, and reconstruct these cell types 3D spatial position information in SCN.this study first found that all kinds of non neuronal cells, including ependymal cells, glial cells, and so on, have extensive expression of rhythm genes, which implies that all kinds of cells in SCN have cell-specific rhythmic function.interestingly, the oscillatory phase of core rhythm genes in all non neuronal cells was significantly later than that in neurons.in neurons, SCN neurons had significantly higher core gene expression than non SCN neurons.the research group further divided the neurons in SCN into five subtypes, which were named AVP + / NMS +, GRP + / VIP +, VIP + / NMS +, CK + / c1ql3 + and CK + / BDNF + (Fig. a-b). in a word, the SCN of circadian rhythm center was comprehensively classified, reconstructed and analyzed for the first time by using advanced single-cell technology in this study. The spatiotemporal gene expression and cellular architecture of different cell types and neuronal subtypes of SCN obtained provide important clues for the study of the neural mechanism of circadian rhythm in mammals. this work can be summarized by f-diagram, implying that SCN, as the core pacemaker of biological rhythm, converts light signals into rhythmic signals like a prism, and different neurons produce different phases of oscillation, which refract to different times on ancient Chinese sundials. in human society, circadian rhythm disorder can lead to various diseases including sleep disorders. Therefore, it is of great significance for human health to understand how circadian rhythm occurs, maintain and play a role in the nervous system. note: the analysis is referenced from the official account of the Institute of neuroscience, Chinese Academy of Sciences. reference message: - end -