Fig 3. Preferential orientation of the dsRNA in spherules.

(A) Schematic of the measurement of the angles between short segments of traced dsRNA and a reference vector anchored to the neck complex and pointing toward the spherule center. (B-D) Hypothetical relative frequency of angles, as defined in A, for the scenarios indicated in the spherule sketches. The dsRNA could pack with no preferred orientation to the neck complex vector (e.g., randomly) (B), with a preferred direction parallel (C), or perpendicular (D) to the neck complex vector. (E) Measurement of the relative frequency of angles in 22 spherules. (F) The traced dsRNA overlayed on a slice through the tomogram for one representative spherule included in the analysis. Scale bar, 25 nm.