The expression analysis of the mir-17–92 cluster in different cell lines. (A) Schematic representation of the Fli-3 gene containing polycistronic miRNA clusters. The striped box (▥) shows the homology region of the murine Fli-3 gene and human C13orf25 gene. The black box (■) shows the region of mature miRNA in the mir-17–92 cluster. The arrow shows the location of the proviral integration site located 298-bp upstream from the cluster. (B) The homology between human and mouse Fli-3 using mVista plot. The high homology region is localized within the mir-17–92 region of both Fli-3 and human C13orf25. (C) Pri-miRNA expression levels in erythroleukemia cell lines were detected by RT-PCR. The size of PCR products is expected to be 314 and 814 bp (for details, see “Materials and methods”). GAPDH was used as loading control. The intensity of CB3 band was used as control (1.0). Fold changes shown at the bottom are mean values derived from 3 experiments. The real-time PCR results are shown at the right panel. The expression of mir-17–92 in CB3 cells was used for calibration. (D) The relative quantities of mir-17–92 expression in normal murine organs detected by the real-time PCR. The expression of mir-17–92 in CB3 cells was used for calibration. Error bars in panels C and D are SD. (E) Pri-miRNA expression levels in erythroleukemia cell lines was detected by Northern blot using mir-17–92 cluster probe derived from the 814-bp PCR product shown in Figure 2C. The 18S rRNA from the ethidium bromide–stained gel was used as loading control. The intensity of KH11 band was used as control (1.0). Mean fold changes are shown at the bottom. (F) Mature miRNA expression was examined in the indicated cell lines by Northern blot analysis using specific oligonucleotide probes corresponding to each mature miRNA from the mir-17–92 cluster. 5S rRNA from the ethidium bromide–stained gel was used as a loading control. A vertical line was inserted to show where a gel lane was cut. The intensity of CB3 was used as control (1.0).