Figure 2.

Classification of lncRNAs based on their genomic location in respect of protein-coding genes. (A) lncRNA categories. Intergenic: lncRNAs are transcribed from intergenic regions; Intronic (S): lncRNAs are transcribed entirely from introns of protein-coding genes; Intronic (AS): lncRNAs are transcribed from antisense strand of protein-coding genes and the entire sequences are covered by introns of protein-coding genes; Overlapping (S): lncRNAs that contain coding genes within an intron on the sense strand; Overlapping (AS): lncRNAs that contain coding genes within an intron on the antisense strand; Sense: lncRNAs are transcribed from the sense strand of protein-coding genes and the entire sequence of lncRNAs are covered by protein-coding genes (Intronic lncRNAs are not included), or the entire sequence of protein-coding genes are covered by lncRNAs (Overlapping lncRNAs are not included), or both lncRNAs and protein-coding genes intersect each other partially; Antisense: lncRNAs are transcribed from the antisense strand of protein-coding genes and the entire sequence of lncRNAs are covered by protein-coding genes (Intronic lncRNAs are not included), or the entire sequence of protein-coding genes are covered by lncRNAs (Overlapping lncRNAs are not included), or both lncRNAs and protein-coding genes intersect each other partially. (B) Proportions of human lncRNAs in different categories.