Figure 1.

Identification and characterization of INXS as an intronic antisense lncRNA downregulated in tumor cell lines. (A) Structure of the BCL-X gene locus on chromosome 20 with the BLC-X protein-coding mRNA being transcribed from the minus genomic strand and the antisense unspliced INXS lncRNA transcribed from the intronic region on the opposite strand. Gray boxes in INXS indicate transcript portions extended by RACE-PCR and sequencing. Small blue arrows next to INXS indicate PCR primers positions. (B) Antisense transcription [AS] of INXS lncRNA was detected by strand-specific RT-PCR in 786-O, DU145 and HepG2 cell lines. Sense transcription [S] was not detected in this locus region. C1 and C2 are negative controls. (C) INXS expression levels across a panel of tumor (light blue) and non-tumor (dark blue) cell lines from kidney, liver, breast and prostate. Absolute quantification of INXS was obtained for each cell line and the relative abundance is shown with respect to the absolute amount measured in the CaKi-1 cell line (175 molecules per ng of total RNA). (D) BCL-XS (black) and BCL-XL (red) mRNA isoform levels across a panel of tumor (T) and non-tumor (NT) cell lines from kidney, liver, breast and prostate. Expression levels are relative to the expression of the BCL-XS isoform in the CaKi-1 cell line. The data are the mean ± SD of three independent experiments. *(P <0.05), **(P<0.01) and ***(P <0.001).