Table_1_Diversity and Emerging Roles of Enhancer RNA in Regulation of Gene Expression and Cell Fate.DOCX

Enhancers are cis-regulatory elements in the genome that cooperate with promoters to control target gene transcription. Unlike promoters, enhancers are not necessarily adjacent to target genes and can exert their functions regardless of enhancer orientations, positions and spatial segregations from target genes. Thus, for a long time, the question as to how enhancers act in a temporal and spatial manner attracted considerable attention. The recent discovery that enhancers are also abundantly transcribed raises interesting questions about the exact roles of enhancer RNA (eRNA) in gene regulation. In this review, we highlight the process of enhancer transcription and the diverse features of eRNA. We review eRNA functions, which include enhancer-promoter looping, chromatin modifying, and transcription regulating. As eRNA are transcribed from active enhancers, they exhibit tissue and lineage specificity, and serve as markers of cell state and function. Finally, we discuss the unique relationship between eRNA and super enhancers in phase separation wherein eRNA may contribute significantly to cell fate decisions.

增强子是基因组中的顺式调控元件，与启动子协同作用以调控靶基因的转录。与启动子不同，增强子并不必然与靶基因相邻，且无论增强子的方向、位置以及与靶基因的空间分隔，均能行使其功能。因此，关于增强子在时间和空间上的作用机制长期以来一直是研究的热点。近期的研究发现增强子同样大量转录，这引发了关于增强子RNA（eRNA）在基因调控中确切角色的一系列有趣问题。在本综述中，我们着重探讨了增强子转录的过程以及eRNA的多样特征。我们回顾了eRNA的功能，包括增强子-启动子环形成、染色质修饰和转录调控。由于eRNA来源于活跃的增强子，它们表现出组织特异性和谱系特异性，并作为细胞状态和功能的标志。最后，我们讨论了eRNA与超增强子之间的独特关系，在相分离阶段，eRNA可能对细胞命运的决定产生显著贡献。