FIG 1.

(A) Organization of S. marcescens arnBCA. Only arnBCA of the arn operon is shown. Arrow, knockout or Tn5-interrupted site for the arnB, arnB(t), or arnC(t) mutant; horizontal line, region amplified by PCR. The product sizes are indicated in parentheses. (B) RT-PCR analysis of arn transcription in wild-type S. marcescens and the arnB(t), arnC(t), and arnB mutants. RT-PCR using the primer pair annealing to arnB/arnC or arnC/arnA (the region shown in panel A) was performed with RNA isolated from overnight cultures of the wild-type and mutant strains. For control reactions, RNA without reverse transcriptase (no RT) or genomic DNA (gDNA) was used as a template. wt, wild-type strain; arnB, arnB-knockout mutant; arnBt, arnB Tn5-mutagenized mutant; arnCt, arnC Tn5-mutagenized mutant.