Fig. 1.

Principle for novel ncRNA discovery. a Identification and classification of ncRNAs based on chromatin signatures. Most mRNA-like lincRNAs are generated from genomic regions with H3K4me3/H3K36me3 signatures; eRNAs originate from activated enhancers with H3K4me1/H3K27ac signatures; the junction site sequences of circSTATB1 were reverse transcribed and inserted into an enhancer with active H3K4me1 signatures. b Sno-lncRNAs maintain their stability by their classical stem-loop structures of snoRNAs. c Alternative splicing within circRNAs. d A number of novel small ncRNAs derived from rRNAs (rRFs), tRNAs (tsRNAs), and snoRNAs (sdRNAs) have also been found to be enriched in RNA-induced silencing complexes (RISCs) and function in a miRNA-like pathway