FIGURE 4.
TRBP asymmetry sensing. The siRNAs in Figure 3 were tested by gel shift assay with recombinant MBP-TRBP for (A) crosslinking, (B) native binding, or (C) native loading control, as described in the text and Materials and Methods. (D) The fraction of siRNA crosslinked by MBP-TRBP was quantified within each lane (fraction crosslinked = crosslinked signal/(crosslinked signal + uncrosslinked signal)). Values are average ± standard deviation; the number of measurements, n, were n ≥ 5 for ‘A’ and ‘G’; n ≥ 3 for ‘S’. M denotes 21 nt single-stranded RNA used as denaturing size marker. Note that EGFP ‘ b’ and ‘d’ siRNAs were interchanged on the gels as compared to the asymmetric or symmetric gel loading. Symbols indicate statistically significant difference for: *, p < 1×10−4; $, p < 1×10−3; and #, p < 1×10−2. For complete statistical comparisons, see Table 6 in the Supporting Information.