Figure 1

Inactivation of hfq in S. aureus (1A) and expression of hfq in S. aureus RN6390 (1B). The complete hfq ORF is removed and replaced by the cat gene (1A). Genes directly up-(mia) and downstream (gpxA₁) of hfq are shown, and primers used for RT-PCR experiments are indicated by arrows. Positions of ORFs related to the N315 annotated genome are respectively: mia (13022047-1302982); hfq (1302997-1303230), gpxA₁ (c1303928-1303452). Total RNAs from post-exponential growth phase cultures of RN6390 WT and hfq mutant strains were first retro-transcribed using random hexamer primers. PCR amplification specific to the hfq ORF was realized from the cDNAs, obtained from random retro-transcription (RT) (1B). Chromosomal DNA of WT (WT chrom. DNA) was used as positive control of PCR amplification. PCR amplification of the spa gene was also used as a positive control of cDNA quality from the RN6390 hfq strain. Negative controls of RT-PCR reactions were also shown (neg. ctl).