Figure 1.

The classification of lncRNA. LncRNA can be subcategorized according to their relationship associated to the protein coding genes. (A) Intergenic lncRNAs are transcribed from the location between annotated protein-coding genes. (B) Intronic lncRNAs are RNA molecules that originate from the intron coding genes in either sense or antisense orientation. (C) Bidirectional lncRNAs are oriented from a location close to protein-coding genes but to an opposite direction. (D) Sense overlapping lncRNAs are transcribed from and overlapped with the sense strands of protein-coding genes. (E) Natural antisense lncRNAs are transcribed from the antisense strands and overlapped with one or several exons/introns. lncRNAs: Long noncoding RNAs.