FRACTIONATION OF RNA-POLYMERASE-II TRANSCRIPTION FACTORS FROM HELA-CELL NUCLEAR EXTRACTS BY AFFINITY-CHROMATOGRAPHY ON DNA-LIKE PHOSPHORYLATED POLYSTYRENE

It was previously shown that phosphorylated cross-linked polystyrene d erivatives specifically interacted with anti-DNA antibodies and anti-p hospholipid antibodies present in the sera of systemic lupus erythemat osus patients. These resins are potential candidates as stationary pha ses in affinity chromatography. We wondered whether these biospecific resins might allow the fractionation of DNA binding proteins such as R NA polymerase II transcription factors from HeLa cell nuclear extracts . Indeed, these proteins play a major role in gene regulation in mamma lian cells and their purification still requires numerous steps. To st udy the biospecificity of DNA-like phosphorylated polystyrene derivati ves, ethanolamine sulfamide crosslinked polystyrene derivatives were p hosphorylated at various rates and HeLa cell nuclear extracts were ads orbed on these resins. Adsorbed proteins were eluted with increasing c oncentrations of aqueous potassium chloride. Collected fractions were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophor esis (SDS-PAGE) and the biological activities of the eluted transcript ion factors were tested by in vitro transcription assay. Results showe d that the elution of transcription factors depended on the substituti on rate in phosphoester groups of the resins. It appears that specific interactions were developed between the polymers and the transcriptio n factors. Moreover, the eluted transcription factors kept their biolo gical activity. These results lead us to propose the purification of R NA polymerase II transcription factors using the phosphorylated polyst yrene resins as stationary phases. (C) 1997 Elsevier Science B.V.