Fig. 1

LncRNA classification based on their genomic location. Classification of lncRNAs (blue) based on their genomic position and in a relation to the neighboring genetic “mRNA” coding sequence (green). Ia) Sense lncRNAs. LncRNAs located in the same genetic chain with same and positive sense as the coding mRNA. Ib) Antisense lncRNAs. LncRNAs located on the opposite coding strand of the mRNA encoding sequences. IIa) Overlapping sense lncRNAs. Overlapped lncRNAs located in the same orientation sense with the mRNA encoding for protein. IIb) Overlapping antisense lncRNAs. Overlapped lncRNAs, located in opposite side with the mRNA encoding proteins. III) Bidirectional or divergent lncRNAs. LncRNAs located on the antisense strand (opposite to the neighboring lncRNA) that share or not promoter genetic sequences whose transcription start site (TSS) is close to the TSS of the coding mRNA sequences (< 1000 bp), meaning that they are transcribed in to the opposite direction with respect to the neighboring “mRNA” coding gene. IV) Intergenic lncRNA. LncRNAs which are transcribed from an intergenic region, transcribing from the sense or antisense strand. V) Intronic lncRNAs. LncRNAs located between the boundaries of the intronic and coding mRNA sequences. The arrow symbols meaning the transcription direction