Role of RNA Polymerase Stimulating Factor on Chain Initiation

Using T4 DNA as template, it has been shown that RNA polymerase purified by phospho‐cellulose chromatography (phospho‐cellulose enzyme) binds to DNA but does not initiate RNA chains. The stimulating factor (σ) released during chromatography does not bind to DNA, but associates readily to phospho‐cellulose enzyme and σ exhibits all the properties of undissociated RNA polymerase with respect to initiation and rate of RNA synthesis, as well as release of long RNA chains.