Transcription of the hut operons of Salmonella typhimurium.

We have measured, by ribonucleic acid-deoxyribonucleic acid hybrid formation, the amounts of hut-specific ribonucleic acid contained in extracts of various mutant strains of Salmonella typhimurium. Our data are consistent with a model in which regulation of Hut enzyme production occurs at the level of transcription and support earlier genetic evidence indicating that all of the hut genes are transcribed in the clockwise direction on the S. typhimurium chromosome. These results also suggest that promoter sites of the two hut operons may differ in their ability to initiate transcription.