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. 2017 Apr 24;7:134. doi: 10.3389/fcimb.2017.00134

Figure 2.

Figure 2

NagC is a transcriptional activator of the LEE genes. (A) Schematic representation of the influence of NANA and NAG on the activity of the transcriptional regulators NagC and NanR. (B) β-galactosidase assays using the PLEE1:lacZ transcriptional fusion integrated into EDL933 or the isogenic mutants ΔnagC and ΔnanR. The strains were grown in DMEM with or without NANA or NAG at 1 mM and harvested at OD600 = 0.6. Results are presented as Miller Units. (C) qRT-PCR measurement of LEE gene expression. EDL933, the isogenic mutant ΔnagC and the complemented strain ΔnagC-c were grown in DMEM with or without NANA or NAG at 1 mM. Results are shown as the ratio copy number of the LEE transcripts/copy number of rpoA transcripts. (D) Western blot analysis of the EspB secretion by EDL933, the isogenic mutant ΔnagC and the complement grown in DMEM with or without NANA or NAG at 1 mM. BSA was used as a loading control. (E) HeLa cells were co-incubated for 90 min with either the wild type EDL933 strain, ΔnagC mutant, the ΔnagC complemented strain or the ΔescN mutant. Adhered bacteria were harvested and counted on agar plates. Results are presented as the percentage of adhered cells compared to the wild type strain EDL933. n ≥ 3, ns for non-significant, *p < 0.05, **p < 0.01, and ***p < 0.001.