One- and two-dimensional histone separations in acidic gels: usefulness of methylene blue-driven photopolymerization.

We tested the recently introduced methylene blue-toluene sulfinate-diphenyl-iodonium polymerization system in order to prepare acetic acid-urea-Triton X-100 gels for histone separations. When compared to standard persulfate-based initiators, this system exhibited several advantages. First, the polymerization proceeds at a much faster rate but is easily controlled since it is light-dependent. Second, no prerunning of the gel was required, since there is no oxidizing molecule able to introduce artifacts. Moreover, this procedure produces gels presenting cleaner backgrounds with silver staining. The ability of the procedure to carry out high resolution two-dimensional electrophoresis of histones was also examined. High resolution two-dimensional gels, using photopolymerized acidic gels as the first or second dimension were obtained.