Size- and concentration-dependent dsRNA transport by SID-1. (A) one or 10 ng/mL of radiolabeled 500 bp dsRNA was added to MT/sid-1 cells at time 0 and 100X unlabeled dsRNA was added at the indicated time points. Internalized radiolabeled dsRNA is reported as molecules/cell. Transport of radiolabeled 500 bp dsRNA shows a rapid initial phase (inset), which appears to be linear and concentration dependent in the first 10 sec. Error bars = 1 standard deviation, n = 4. (B) Retention at 10 and 300 sec of 100 bp and 500 bp dsRNA added at equimolar concentrations. Approximately twice as much 100 bp dsRNA was retained at both time points. For data presentation, CPM in uninduced cells were subtracted from the counts measured in induced cells. Error bars = 1 standard deviation, n = 2.
