Fig. 4: Low leucine levels repressed NsrP expression via Lrp.
a qRT-PCR analysis of NsrP expression in the NMEC WT strain in LB medium and mouse blood. b The NsrP promoter region and the potential binding site of Lrp were predicted by the BProm program (SoftBerry). c qRT-PCR analysis of the NsrP expression in WT and Δlrp. d Biacore SPR kinetic analyses of Lrp binding to the promoter of NsrP. e Fold enrichment of the NsrP promoter in the Lrp-ChIP samples compared with that in the mock-ChIP samples. f qRT-PCR analysis of the NsrP expression in WT NMEC in M9 medium supplemented with 0.1 mM leucine (Leu-L) or 5 mM leucine (Leu-H). g Northern blotting of NsrP sRNA in WT NMEC in M9 medium supplemented with 0.1 or 5 mM leucine. 5S rRNA was used as the loading control. h, i qRT-PCR analysis of the NsrP expression in the Δlrp (h) and NsrPpro-mut (i) strain in M9 medium supplemented with 0.1 or 5 mM leucine. In a, c, e–i, data were presented as the means ± SDs (n = 3 independent experiments). ns nonsignificant. Two-tailed unpaired Student’s t-test (a, c, f–i) and two-way ANOVA (e) were applied.
