Identification of transcription start sites. Transcription start sites were identified by the 5' RACE method in E. coli containing pKKlux derivatives with fusions between the promoterless luxAB genes and the promoter from the nptIII gene (P NPTIII), the promoter from the TEM-1 gene (P BLA), the polyhedrin promoter (P PH) and the immediate early CMV promoter (P CMV). The sequences shown cover the transcription initiation sites identified in E. coli (indicated by arrows) and their upstream regions. The putative -10 and -35 regions are underlined. Two transcription start sites [a), b)] were identified in the P CMV.