Figure 3

Primer extension analysis of short-and long-form X. nematophila tdk transcripts in E. coli. Total RNA was isolated from E. coli KY895 carrying plasmids pTara and pETSTdk or pETLTdk grown overnight to OD₆₀₀ = 2.0. Primer tdkprext2 was end-labeled with ³²P and used to produce a sequencing ladder from plasmids pETSTdk (left side; lanes C, T, A, G) and pETLTdk (right side; lanes C, T, A, G). A primer extension product was produced with end-labeled tdkprext2, total RNA template (left side: KY895 carrying pETSTdk; right side: KY895 carrying pETLTdk) and AMV-RT enzyme at 37°C (lanes "pe"). Arrows indicate the expected transcriptional start site from the T7 promoter of pET-28a(+).