Figure 2From: Chromatin signatures at transcriptional start sites separate two equally populated yet distinct classes of intergenic long noncoding RNAselncRNA and plncRNA loci have similar sequence features. (A) The lengths of elncRNA (enh-TIR, median = 293 nucleotide, green) and plncRNA (prom-TIR, median = 342 nucleotide, blue) TIRs are similar (two-tailed Mann–Whitney test, P = 0.52), (B) as are the lengths of elncRNA (median = 1006 nucleotide) and plncRNA (median = 903 nucleotide) transcripts (two-tailed Mann–Whitney test, P = 0.24). (C) The percentage of elncRNAs that are mono-exonic (47%, dark green) is similar to that for plncRNAs (54%, dark blue, two-tailed Fisher’s exact test, P = 0.37). Light green and blue represent the percentage of multiexonic elncRNAs and plncRNAs, respectively. (D) Relative transcriptional orientation for lncRNAs (black) and their closest protein-coding gene (grey). For simplicity lncRNAs are represented here as transcribed from 5′ to 3′. Arrow represents the direction of transcription. (E) Percentages of lncRNA-protein-coding gene pairs with relative orientation head-to-head (white; elncRNAs = 31%, plncRNAs = 41%); tail-to-tail (light-grey, elncRNAs = 45%, plncRNAs = 35%); tail-to-head (dark-grey; elncRNAs = 19%, plncRNAs = 14%) and head-to-tail (black; elncRNAs = 5%, plncRNAs = 10%). (F) Total number of polyA selected RNA sequencing reads (y-axis) associated with the transcriptional start sites of protein-coding gene (black), elncRNA (green) and plncRNA (blue) meta-genes’ transcriptional start sites (±50 bp, x-axis). Arrow indicates the location of the transcriptional start site and the direction of the meta-gene transcription. NS, not significant.Back to article page