Widespread coupling of promoters and terminators of transcription in bacteria

Abstract

Transcription underpins the expression of genetic information and is viewed as a series of independent initiation and termination events. In bacteria, promoters and terminators of transcription are therefore considered distinct regulatory elements. Here, we challenge this view. Genome-scale analyses reveal that promoters and terminators are extensively coupled. Thus, initiation and termination sites, for adjacent transcription units, frequently overlap. This conserved organisation arises because the DNA sequences, which direct termination, also contribute to promoter function. This couples neighbouring transcription units and generates regulatory interference between RNA polymerases. These findings define a universal mechanism for coordinating transcription across bacterial genomes.