Figure 4

Isoforms of the hsa-miR-30 family. The hsa-miR-30 family comprises of a large number of overlapping mature miRNA sequences that might interfere with expression profiling. Mapping HTS reads to the human genome (pipeline A) detects 4 significantly overlapping sequences shown as hairpin sequences in A. Open boxes mark the sequences of mature 5′ miRNAs that were further validated. The sequence part that allows differentiation between the family members is marked in grey. The seed sequence common to all members is shown in lower case. (B) Currently, only high-throughput sequencing can clearly differentiate between hsa-miR-30 family members, additionally providing a chance to evaluate expression of hsa-miR-30e isoforms – 30e-1 and 30e-2. Means of miRNA expression in 20 samples using HTS data and qPCR for hsa-miR-30e-5p and interfering sequences (i.e. 30a, c and d) are listed. Although using specific forward and reverse primers for the detection of isoforms of the hsa-miR-30 family, qPCR that targets specific hsa-miR-30 family members clearly lacks specificity to detect 1 base changes in the target sequence. *- HTS pipeline A detection of the hairpin sequence for has-miR-30e. **- Pipeline C generates a sum of all isoforms with the same seed sequence.