In vitro transcription and RNAP promoter complex formation in the presence of C.Kpn2I. ( A ). Results of multiple-round transcription by σ 70 RNAP holoenzyme with wild-type ('wt') α subunit or with α lacking the CTD domain ('-αCTD') from a DNA fragment containing the intergenic region between kpn 2I .M and kpn 2I .C in the presence or in the absence of added C.Kpn2I. ( B ) The same DNA fragment was combined with σ 70 RNAP holoenzyme, C.Kpn2I, or both and subjected to DNase I footprinting. ( C ) As in B but showing the results of KMnO 4 probing of complexes formed by σ 70 RNAP holoenzymes with wild-type α or α lacking the CTD. ( D ) Results of multiple-round transcription in the presence or in the absence of C.Kpn2I by RNAP holoenzymes containing wild-type σ 70 or σ 1–565 lacking the region 4 domain. In addition to transcription from the kpn 2I .M promoter, results of transcription from strong -10/-35 class promoter T7 A1 and extended –10 class gal P1 promoter are shown.