Cloning and characterization of a transcription termination signal in bacteriophage λ unresponsive to the N gene product

The pHA10 plasmid was designed for the cloning and selection of transcriptional termination signals. This study demonstrates the use of pHA10 as a cloning vehicle in the selection and characterization of an N-unresponsive terminator. Following the random cloning of λ DNA, an N-unresponsive transcription terminator was isolated. Hybridization of in vivo ³²P-labeled RNA to various DNA fragments, using the Southern (1975) blotting technique, revealed that the transcriptional barrier that cannot be overridden in the presence of N is located close to the end of gene J of λ DNA. The terminator determines the 3'-end of the fpl opsron and prevents the transcription of the anti-sense DNA strand of λ late genes. The primary structure and other characteristics of this terminator are now under investigation.