[The emerging landscape of long non-coding RNAs].

With the completion of Human Genome Project (HGP), it was revealed that among the 3 billion base pairs in human genome, only 1.5% of them encodes proteins. The remaining 98.5% of the sequence does not encode any protein, and was once regarded as accumulated junk sequences during evolution. However, in the subsequently initiated ENCODE project, it was unexpectedly found that about 75% of the human genome was transcribed into RNAs. Seventy-four percent of them are non-protein-coding RNAs (non-coding RNAs, ncRNAs). In this RNA category, most of the transcripts are longer than 200 nucleotides and thus named as long non-coding RNAs (lncRNAs). ncRNAs regulate gene expression at the transcriptional and post-transcriptional levels, function in fundamental biological processes including cell differentiation and organ development, and are closely associated with many human diseases. In this paper, we review the recent progress in the discovery, classification, expression, and function study of lncRNAs, as well as their roles in the pathogenesis of hu-man diseases.