Preparative high-resolution two-dimensional electrophoresis enables the identification of RNA polymerase B transcription factor 3 as an apoptosis-associated protein in the human BL60-2 Burkitt lymphoma cell line

Apoptosis or programmed cell death is essential in the process of controlli ng lymphocyte growth and selection. We identified RNA polymerase B transcri ption factor 3 (BTF3), which is associated with anti-IgM antibody-mediated apoptosis, using a subclone of the human Burkitt lymphoma cell line BL60. T o identify the transcription factor BTF3, which is expressed only in minor amounts, we used preparative high-resolution two-dimensional gel electropho resis (2DE) employing carrier ampholytes for isoelectric focusing. Comparis on of the 2DE protein patterns from apoptotic and nonapoptotic cells showed BTF3 as a predominantly altered protein spot. The characterization of the differentially expressed transcription factor and 13 marker proteins descri bed in this study were performed by internal Edman microsequencing and/or b y peptide mass fingerprinting using matrix-assisted laser desorption/ioniza tion mass spectrometry (MALDI-MS). The proteome analysis was significantly improved by performing the newly developed preparative high-resolution two- dimensional gels employing high protein concentrations.