Figure 4.

Dose response relationship for siCAG. (a) The level of CUG^exp transcript was determined by northern analysis in tibialis anterior (TA) muscle. Four doses of siCAG (3, 1, 0.3, or 0.1 µg) were electroporated into TA of human skeletal actin—long repeat mice (n = 2 per each group). Total RNA was isolated after 7 days. Saline electroporated TA serves as control. (b) RT-PCR analysis of alternative splicing for mice described in (a). The two higher siCAG doses produced strong splicing correction, while the lowest dose had no effect. (c) Reduction of myotonia 1 week after electroporation of siCAG into TA muscle. The contralateral TA was electroporated with saline alone (n = 2 mice for each siRNA dose; *P < 0.0001 for siCAG versus saline according to Student's t-test). Myotonic discharges were rated by a blinded examiner using extracellular needle electrode recordings (electromyography) under general anesthesia. Myotonia was significantly reduced in muscles treated with 3 and 1 µg of siCAG. HSA^LR, human skeletal actin—long repeat mouse; WT, wild type mouse. **P < 0.05.