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. 2007 Dec 15;36(1):e4. doi: 10.1093/nar/gkm1084

Figure 3.

Figure 3.

Confirmation of 23S rRNA deletions. (A) Agarose gel showing PCR products generated from gDNA of select E. coli strains. Strain RS526 (WT rrl) has all rRNA operons intact and yields large (∼4–5 kb) PCR products when the 16S and operon-specific primers are used (Figure 2). The ΔrrlDGH strain (RS547) shows smaller PCR fragments demonstrating the deletion of 23S rRNA genes from the respective operons. Lastly, strain RS676 (ΔrrlABDEGH) has only one copy of the gene for 23S rRNA located in the rrnC operon. Lanes 1 and 23: Marker DNA (1 kb ladder and 0.1 kb ladder, respectively). (B) Southern blot demonstrating the step-wise removal of 23S rRNA genes from six of the seven operons. The sizes of the DNA bands and corresponding operons follow: rrnC—16.9 kb; rrnG—15.5 kb; rrnE—11.2 kb; rrnH—9.6 kb; rrnD—8.1 kb; rrnB—7.2 kb and rrnA—6.6 kb. Strain designations: WT- RS526, Δ1- RS537, Δ2- RS544, Δ3- RS547, Δ4- RS550, Δ5- RS554 and Δ6-RS676.