Electrophoretic heterogeneity of grapevine histones

Histones from grapevine leaves were isolated using classical extraction pro cedures. Different electrophoretic processes were tested to study the heter ogeneity of grapevine histones. Polyacrylamide gels containing sodium dodec yl sulfate were useful for the fractionation of grapevine histone H1, H3, a nd H4 classes but inefficient for the isolation of histone H2A and H2B clas ses. Gels containing Triton X-100, used for the second dimension in two-dim ensional electrophoresis, proved to be more efficient for the separation of all histone classes, as well as for that of their subfractions (structural variants and/or chemical modified forms) and resulted in optimum fractiona tion of grapevine nucleosomal proteins. The core histone H2B fraction, whic h is very sensitive to oxidation, seems to consist of a large number of sub fractions, forming three sets of proteins with different mobility in polyac rylamide gels containing acetic acid, urea, and Triton X-100 (AUT-PAGE). Hi stones H1, H2A, and H3 also display internal heterogeneities with three for ms for histone Hl,four forms for histone H2A, and two forms for histone H3. In an attempt to define which of the Triton X-100 resolved subfractions re presents oxidation forms, experimental oxidation of grapevine histones was performed.