A biochemical assay for the transcription-antitermination function of the coliphage lambda N gene product.

An in vitro assay has been developed for the antiterminating activity of the N gene product (pN) of bacteriophage lambda, based on the N-dependent stimulation of trp mRNA synthesis from the DNA templates of lambda trp transducing phages. Using this assay system, we show (a) that the stimulation of trp mRNA synthesis by pN requires the cis-dominant nutL site on the lambda chromosome and (b) that pN can participate in vitro in the formation of functional antiterminating transcription complexes.