Howard Hughes Medical Institute, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0648, USA.
Nat Rev Genet. 2016 Apr;17(4):207-23. doi: 10.1038/nrg.2016.4. Epub 2016 Mar 7.
Networks of regulatory enhancers dictate distinct cell identities and cellular responses to diverse signals by instructing precise spatiotemporal patterns of gene expression. However, 35 years after their discovery, enhancer functions and mechanisms remain incompletely understood. Intriguingly, recent evidence suggests that many, if not all, functional enhancers are themselves transcription units, generating non-coding enhancer RNAs. This observation provides a fundamental insight into the inter-regulation between enhancers and promoters, which can both act as transcription units; it also raises crucial questions regarding the potential biological roles of the enhancer transcription process and non-coding enhancer RNAs. Here, we review research progress in this field and discuss several important, unresolved questions regarding the roles and mechanisms of enhancers in gene regulation.
调控增强子网络通过指导基因表达的精确时空模式，决定不同细胞的身份和对各种信号的细胞反应。然而，在发现它们 35 年后，增强子的功能和机制仍不完全清楚。有趣的是，最近的证据表明，许多（如果不是全部的话）功能增强子本身就是转录单元，产生非编码增强子 RNA。这一观察结果为增强子和启动子之间的相互调节提供了一个基本的认识，因为它们都可以作为转录单元；它还提出了关于增强子转录过程和非编码增强子 RNA 的潜在生物学作用的关键问题。在这里，我们回顾了这一领域的研究进展，并讨论了几个关于增强子在基因调控中的作用和机制的重要、未解决的问题。
