Fig 4.
Expression of fliL operon genes and flaA in pseudoswarmer cells. (A) Organization of the fliL operon in BB2000, BB2204, and YL1001. Mini-Tn5-Cmr (∼2 kb) disrupts fliL2204 at nucleotide 440, and fliLYL1001 is mutated by a 68-bp scar following excision of the transposon. The fliL promoter is indicated by a bent arrow, and open circles represent transcriptional terminators in the mini-Tn5 transposon. (B) RT-PCR analysis of transcription of class II (fliL and fliM) and class III (flaA) flagellar genes, relative to rpoA (as a positive referential control). Lanes: 1, BB2000; 2, BB2204; 3, YL1001. RT(+) indicates complete reverse transcriptase PCR, while RT(−) lanes lack reverse transcriptase and serve as a control for DNA contamination.