Long non-coding RNAs: Guardians of development.

Two decades ago, the existence of long non-coding RNAs (lncRNAs) was discovered. In the following genomics era more transcribed non-coding genomic regions were identified. These were initially regarded as transcriptional noise and did not receive a lot of attention. Emerging data on several of these long non-coding transcripts have refuted this hypothesis by demonstrating that non-coding RNAs (ncRNAs) are important for regulating transcription and cell signaling. A special subset of the lncRNAs affecting gene transcription appears to orchestrate major developmental programs. Here, we discuss the mechanisms by which lncRNAs regulate transcription, and review the evidence that links this class of lncRNAs to a role in development.