The purification and properties of hen oviduct form B DNA-dependent RNA polymerase

Hen oviduct form B DNA-dependent RNA polymerase has been extensively purified and its properties analysed. It seems likely to consist of a mixture of two forms of the type observed in tissues from other species. Furthermore using S1 nuclease to digest single-stranded DNA, we show that although form B can transcribe double-stranded DNA template it has a very strong preference for single-stranded regions. Also the rate of elongation on native DNA in vitro was measured and is an order of magnitude slower than that reported to be operative in vivo.