FIG 4.

Screen for infection-induced ProQ-dependent sRNAs. (a) Dual RNA-seq data on the expression of ProQ-associated sRNAs (as defined in references 13 and 22) during a high-resolution time course of the infection of HeLa cells by wild-type Salmonella. Expression data were retrieved from a previous study (30) (accession number GSE117256). (b) Comparative expression of ProQ-associated infection-induced sRNAs (colored in panel a) between ΔproQ strain and the wild-type Salmonella at the indicated time points after HeLa infection. The results stem from two biological replicate experiments. (c) Northern blot on the expression of the denoted sRNAs. Total RNA samples were taken from wild-type Salmonella grown under the indicated in vitro conditions, separated on a 6% PAA/urea gel, blotted, and probed with sRNA-specific DNA oligonucleotides (Table S1G). OD, optical density (in LB); ON, overnight growth in LB; SPI-2, SPI-2-inducing conditions (see Materials and Methods). (d and e) Northern blot data for the same sRNAs in the presence or absence of ProQ (d) or Hfq (e) in ESP (LB; OD 2.0) or SPI-2-inducing conditions. Detection was performed as described above for panel c. 5S rRNA serves as loading control in panels c to e.