Interaction of RNA polymerase II general transcription complex proteins with oligoribonucleotides

Saccharomyces cerevisiae RNA polymerase II general transcription complex proteins (RNA polymerase II, TBP, TFIIB, TFIIF, TFIIE, and TFIIH) were tested for interaction with oligoribonucleotides. Electrophoretic mobility shift assays showed that 32P-labeled CU-rich oligonucleotide p-17 (5'-ACUCUCUUCCGCAUCGC-3') interacted with the proteins to yield three types of complexes, corresponding to three retardation bands. All complexes were RNA-specific, because [P-32]p-17 was displaced by an excess of nonlabeled S. cerevisiae RNA and was not displaced by a 500-fold molar excess of a nonlabeled oligodeoxyribonucleotide. The complexes corresponding to the middle retardation band were specific for p-17, because [P-32]p-17 was displaced almost completely by a 100-fold molar excess of nonlabeled p-17 and was not displaced by a 500-fold molar excess of an AU-rich oligoribonucleofide. The complexes corresponding to the upper retardation band were RNA-specific, and those corresponding to the lower band were assumed to result from nonspecific sorption of [P-32]p-17 on a protein. Oligoribonucleotides and olioligodeoxyribonucleotides did not compete for the binding with RNA polymerase II general transcription complex proteins.