Effect of salts on abortive and productive elongation catalysed by wheat germ RNA polymerase II

Modification of the ionic conditions in reaction assays containing wheat germ RNA polymerase II and poly(dAT) as template markedly alters the catalytic properties of the transcription complexes. These effects have been studied by measuring the rate of abortive initiation and the extent of productive RNA synthesis. Using combinations of metal ions or various salts, a marked inhibition of abortive initiation was always associated with an increased length of RNA chains. These results are discussed in terms of modulation of the stability of transcription complexes induced by salts or divalent cations. The behavior exhibited by wheat germ RNA polymerase II is also discussed in comparison with previously reported results for procaryotic and eucaryotic RNA polymerases.