Rotating Field Gel Electrophoresis (ROFE)

Rotating field gel electrophoresis (ROFE) (1 –4 ) is an alternative to orthogonal field alternating (OFAGE) (5 ), transverse alternating field (TAFE) (6 ), field inversion (FIGE) (7 ), or related pulsed-field gel electrophoretic procedures for the separation of very large nucleic acid molecules. The latter methods all involve the electronic switching between two electric fields oriented at an obtuse angle (or 180� in FIGE) toward each other. In ROFE, the anodes and cathodes are carried by a rotor that can be turned around the stationary gel in which the separation takes place. The electric field, generated between two main electrodes and stabilized with electronically regulated additional sets of electrodes, can be reoriented after predetermined intervals (Fig. 1 ). In principle, this leads to a separation of DNA molecules in the gel analogous to that obtainable with devices using purely electronic switching.