Figure 2.

lncRNAs, according to the transcription locus relative to protein-coding genes, are classified as sense, antisense, intronic, intergenic, and bidirectional. The blue represents genes of lncRNAs; the gray represents the protein-coding genes or exons of protein-coding genes, and the arrow is the transcription direction. Sense: lncRNAs transcribe from the same strand of protein-coding genes with overlapping; antisense: lncRNAs transcribe from the antisense strand of the strand of protein-coding gene with overlapping; intron: lncRNAs entirely transcribe from the intron of protein-coding gene; intergenic: lncRNAs lie in two protein-coding genes; bidirectional: lncRNAs, in the same strand of protein-coding gene, perform the opposite transcription direction.