Transcriptional Analysis of the salKR Locus and its Flanking Sequences 
To confirm the predicted transcripts of salKR and the flanking genes, RNA extracted from S. suis 05ZYH33 cells was subjected to RT-PCR analysis by using primers amplifying each intergenic region of salKR and the flanking genes.
As shown in Fig. 2B, RT-PCR products were obtained with five pairs of the primers (P3/P4, P5/P6, P7/P8, P9/P10 and P13/P14), but not with the other three primer pairs (P1/P2, P11/P12 and P15/P16).
On the other hand, when genomic DNA was used as a template, all these primer pairs yielded the expected PCR products (Fig. 2B, PCR).
These results suggested that salK and salR are transcriptionally coupled, and the five downstream (05SSU0942-05SSU0938) genes are co-transcribed from a promoter positioned immediately upstream of 05SSU0942 and that their transcription ends between the 05SSU0938-05SSU0937 intergenic region which contains a terminator-like inverted repeat sequence.
