MiRNA Genes Constitute New Targets for Microsatellite Instability in Colorectal Cancer
Figure 5
Secondary structures of WT and mutated hsa-mir-1303 and expression levels of miR-1303 in CRC cell lines.
A: Alterations in repeat sequences of hsa-mir-1303 (A) and its variant (delA) did not seem to affect overall the secondary structure of the hairpin but the dimension of the loop (annoted inside) is slightly reduced as determined by mfold software (http://mfold.rna.albany.edu/). Mature miR (bold letters) and MNR (underlined letters) are shown in both hairpin sequences. The arrows indicate the potential positions of an Adenine deletion that leads to an enlargement of the loop. B: Comparison of the relative expressions of mature miR-1303 in MSS (unaltered MNR) and MSI CRC cell lines with none, mono- or bi-allelic mutations of hsa-mir-1303. MiR expression was normalized to the expression of RNU48. Means are shown for each group (black horizontal line). A significant increase in the expression of miR-1303 was observed between MSS cell lines and normal colonic mucosae (p = 0.012). C: Absence of correlation between the size of mir-1303 loop and the levels of mature miR-1303 expression in MSI cell lines with no (HCT-8, TC7) or bi-allelic mutations (LS411, RKO, LIM2405, KM12, LoVo, HCT116) in MNR of hsa-mir-1303. Note cell lines that produce hairpin precursors with the same size of the loop do express mature miR-1303 at various levels.