Quantitative Proteomics for Two-Dimensional Gels Using Difference Gel Electrophoresis

Difference gel electrophoresis (DIGE) technology provides a powerful quantitative component to proteomics experiments involving two-dimensional (2D) gel electrophoresis. DIGE allows for the detection of subtle changes in protein abundance with statistical confidence while controlling for gel-to-gel variation, as well as additional variation that is non-biological in origin (e.g., sample preparation error, normal variation in a system). Samples are differentially labeled with spectrally resolvable fluorescent dyes (Cy2, Cy3, and Cy5) and co-resolved for direct quantification within the same 2D gel. Increased statistical confidence is obtained when combining experimental repetition with internal standards such that independent replicate measurements from single- and multivariable analyses can be intercompared with a relatively small number of coordinated DIGE gels.