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. 2012 Mar 13;3(2):e00312-11. doi: 10.1128/mBio.00312-11

FIG 5 .

FIG 5

Detection of transcription by a cryptic promoter upstream of the SP6 promoter. (A) SP6 promoter-SML transcription unit and the locations of primers UpSt and DnSt, used to amplify SML RNA, are indicated. The primer SP6-Dep-UpSt overlaps the SP6 promoter and terminates one nucleotide 5′ to the transcription initiation site for SP6 polymerase. (B) RNA purified at 4 h p.i. from H37Rv M. tuberculosis infected with phSP6-ProPol was digested with DNase I prior to reverse transcription with the DnSt primer. A portion of cDNA was then left undiluted or diluted 1:10 and was PCR amplified using the primers DnSt and UpSt or DnSt and SP6-Dep-UpSt. The targeting plasmid pSP6-ProPol-Kan was included in separate amplification reactions as a control for successful PCR using each primer set. Products were then separated on a 2% agarose gel and visualized by ethidium bromide staining. The locations of DNA size markers are indicated.