Figure 5.

Pre-mRNA splicing is not required for cropping. (A) Reporter constructs. Upper row: wild-type BCL2L2 mRNA (exon: filled box; intron: solid line). The miRNA stem–loop was inserted into the EcoRI site in the intron. Middle row: miRNA-inserted construct. Lower row: splicing-deficient form of miRNA-inserted construct (red dots indicate the sites of mutation). The mutated sequences are indicated in red. (B, C) RT–PCR and Northern blotting. Reporter constructs were transfected into HEK293T cells and, 2 days later, total RNA was extracted for RT–PCR and Northern analysis. In panel C, the band indicated with an asterisk (^*) represents other members of the endogenous let-7a family. 18S rRNA stained with EtBr is shown as loading control.