中文摘要：

长链非编码RNA（Longnon．codingRNA，lncRNA）发现是基因组学和分子生物学研究领域的重要进展。lncRNA在生命活动中具有重要的调节功能，其表达紊乱与多种人类疾病的发生发展密切相关。研究表明，几乎所有的调控性lncRNA通过与不同种类的生物大分子，如DNA、RNA和蛋白质发生相互作用而行使其功能。文章概述了lncRNA在表观遗传学水平、转录水平及转录后水平调控基因表达的效应机制，并探讨了lncRNA如何在肿瘤发生和宿主防御过程中行使功能。不同于小分子ncRNA通过碱基互补配对调控靶基因的表达，大多数已鉴定的lncRNA通过调节蛋白质活性或维持蛋白质复合物的完整性发挥其生物学功能。因此，鉴定lncRNA．蛋白质相互作用可能是理解lncRNA功能的首要任务。

英文摘要：

Advances in genomics and molecular biology have led to discovery of a large group of previous uncharacter- ized long non-noncoding RNAs （lncRNAs）. Whether all of these transcripts are functional remains to be elucidated, but emerging evidence indicates that many IncRNAs play roles in multiple biological processes and that dysregulation of lncRNAs is often associated with diseases. Of significant interest, recent studies suggest that almost all of the regulatory lncRNAs function through interacting with different biological macromolecules such as DNA, RNA, and protein. In this review, we summarize the mechanisms by which lncRNAs regulate gene expression at epigenetic, transcriptional and post-transcriptional levels, and discuss the role of lncRNAs in tumorigenesis and host defense. Distinct from small ncRNAs that regulate gene expression mainly through base pairing to target transcripts, most identified lncRNAs function by regu- lating protein activity or maintaining the integrity of protein complexes. As a result, identification and characterization of the lncRNA-protein interactions may be the primary task to decode functional lncRNAs.