Figure 7.

Two-dimensional gel electrophoresis. (A) The first electrophoresis is a conventional PAGE with native conditions. Circular (c) and linear (l) viroid RNA can not be visualized by standard staining techniques due to the high background of other nucleic acids (gray). After electrophoresis the lanes a and b are cut from the gel; these are polymerized at the bottom of a new gel matrix. (B) Due to the denaturing conditions used for the second dimension, the circular viroid, which migrates very slowly, is well separated from other nucleic acids. Modified from (101).