中国神经再生研究(英文版) ›› 2022, Vol. 17 ›› Issue (1): 82-84.doi: 10.4103/1673-5374.315229

• 观点:神经损伤修复保护与再生 • 上一篇    下一篇

解读突触活动的转录组学特征

  

  • 出版日期:2022-01-05 发布日期:2021-09-18

Deciphering the transcriptomic signature of synaptic activity

Guido Hermey*   

  1. Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany 
  • Online:2022-01-05 Published:2021-09-18
  • Contact: Guido Hermey, PhD, guido.hermey@zmnh.uni-hamburg.de.

摘要:

Neural Regen Res:转录和蛋白质组多样性是突触功能调节和多样化所必需的
神经元的分子组成和结构发生活性依赖性变化,以调节细胞过程,如树突生长、突触消除、脊柱成熟和突触强度。这种突触可塑性在大脑发育的关键时期起着重要作用,有助于成熟神经系统的感觉适应和学习记忆。短期活性依赖性突触改变主要依赖于已有蛋白质的翻译后修饰,而突触适应的长期维持则依赖于基因诱导。从突触到细胞核的信号激活基因表达。这些信号被认为是编码在钙波中或由运动蛋白逆行转运的大分子信号复合物传递。诱导的基因转录和蛋白质合成改变了突触蛋白质网络的组成,并提供了将突触活动转化为持续性突触改变的机制。在过去的几十年里,大量的基因表达水平受到突触活动的调控。其中一些基因编码的蛋白质调节突触功能,并在神经元可塑性相关过程中发挥作用。然而,必须考虑的是,改变的基因表达水平只是复杂活动调控的转录信号的一部分。选择性剪接,外显子序列的差异包含和排除,结合其他相关过程,如使用替代转录起始位点和替代多聚腺苷酸化位点以及mRNA编辑,确保突触功能调节和多样化所需的转录组和蛋白质组多样性。Homer1作为活性诱导的选择性剪接的原型,不同类型的选择性剪接决定了不同的Homer1亚型。Homer1a表达的功能相关性已经被证实,而Ania3和Homer1d的功能研究仍然很少。
来自德国汉堡大学医学中心的Guido Hermey认为未来的研究应该确定Homer1d和其他长的异构体是否具有功能,或者Homer1d是否干扰它们的功能。尽管Homer1剪接对突触可塑性很重要,但大量其他基因的选择性剪接受突触可塑性的调控。需要生成和分析额外的数据集,以涵盖特定异构体的差异活性调节表达、诱导动力学和刺激特异性。到目前为止,大多数差异剪接的全基因组分析都依赖于短读RNA测序的连接读取,在短读RNA测序中,不能明确定位的读取可能会影响异构体的检测。尽管短读平台目前占主导地位,因为它们提供了更高的吞吐量,但在未来的研究中,有望考虑采用替代的长读技术,实现单个RNA分子的单分子测序,重点关注异构体的发现。这种长时间阅读的RNA测序方法揭示了全长转录本的阅读可以提供更好的异构体水平的数据,并将大大提高对差异剪接基因的认识。从不同的实验模型和物种中产生这样的综合数据集将有助于未来的比较研究,以提供转录组学特征的综合视图。它将提高我们对选择性剪接的调控和表观遗传机制、其进化保守性以及对突触可塑性的贡献的理解。
    文章在《中国神经再生研究(英文版)》杂志2022年 1 月 1 期发表。

Abstract: Neurons undergo activity-dependent changes in their molecular composition and structure in order to regulate cellular processes such as dendritic growth, synapse elimination, spine maturation and synaptic strength. Such synaptic plasticity plays an important role during a critical period in brain development and contributes to sensory adaptation and to learning and memory in the mature nervous system. Its dysregulation underlies a number of pathological processes in psychiatric and neurodegenerative disorders, such as addiction, depression, anxiety, schizophrenia, epilepsy and traumatic brain injury. Short-term activity-dependent synaptic changes rely mostly on post-translational modifications of pre-existing proteins, whereas the long-term maintenance of synaptic adaptations depends on gene induction. Signals from the synapse to the nucleus activate gene expression. Such signals are thought to be encoded in calcium waves or conveyed by macromolecular signaling complexes translocated retrogradely by motor proteins. The induced gene transcription and protein synthesis alters the composition of synaptic protein networks and provides a mechanism for translating synaptic activity into persistent synaptic changes. In accordance, large sets of genes whose expression levels are regulated by synaptic activity have been described in the past decades. As expected, several of these genes encode proteins that modulate synaptic function and play a role in neuronal plasticity-related processes. However, it has to be considered that altered gene expression levels are only part of the complex activity-regulated transcriptional signature. Alternative splicing, the differential inclusion and exclusion of exonic sequence, in combination with other related processes such as the use of alternative transcriptional initiation sites and alternative polyadenylation sites as well as mRNA editing ensure the transcriptomic and proteomic diversity required for the regulation and diversification of synaptic functions.