Figure 1

Generation of miR-206/133b knock-out mice. The miRNAs miR-206, miR-1 and 133a/b are encoded in three clusters on mouse chromosome 1, 2 and 18. The primary sequence (A) of mature miR-1/133a encoded on chromosome 2 and 18 is identical, miR-206 differs in four bases from miR-1, and miR-133b differs in one base from miR-133a (red). The seed sequence, which is instrumental for target binding of miRNAs, is identical between the corresponding miRNAs (blue). Schematic representation of the miR-206/133b genomic region (B) with deleted parts indicated (red). Southern blot analysis (C) of genomic DNA isolated from wildtype (WT), heterozygous, and homozygous mutant animals proves deletion of the miR-206/133b locus. An SphI digest of genomic DNA and a probe hybridizing 5′ prime of the targeting vector were used to monitor targeting of the miR-206/133b locus by homologous recombination. RNase protection assay (D) and northern blot (E) analysis demonstrates the loss of miR-206 in the soleus muscle of knock-out animals. Expression of miR-1 is not changed in soleus muscle of miR-206/133b knock-out mice.