Transcriptional organization of the S10, spc and α operons of Escherichia coli

Abstract

We have investigated the transcription patterns at the inter-operon regions between the S10 and spc, and spc and α ribosomal protein operons of Escherichia coli. Newly synthesized transcripts were characterized by RNase T1 protection experiments, and accumulated transcripts were mapped with S1 nuclease. With both techniques we found that about 75% of the RNA polymerases transcribing the S10 operon terminated at the position of a typical ϱ-independent terminator. In contrast, most or all RNA polymerases transcribing the spc operon continued into the α operon. Nevertheless, we observed that about 30% of the transcripts of the α operon were initiated at the α operon promoter.