Fig. 6: NtcA binds to the promoter region of the ftsZ gene in the presence of 2-OG (2-oxoglutarate).

A Diagram of the positions of the TSS sites of ftsZ (indicated by a polyline arrow), the putative NtcA-binding motifs (in orange) at the promoter region of ftsZ, and the DNA fragments (indicated as ftsZ1 and ftsZ2) used for the assays. B EMSA assays demonstrate the binding of NtcA to the two putative motifs, ftsZ1 (B) or ftsZ2 (C), in the presence of 2-OG. In (B) and (C), the Left panel, two FAM-labeled DNAs, ftsZ1 or ftsZ2 (2 pmol), were first incubated with increasing concentrations of the NtcA protein. Right panel, 2 pmol DNA fragments were incubated with 4 pmol NtcA in the absence or the presence of increasing concentrations of 2-OG. D Statistical analysis of GFP fluorescence in the WT and the gPCEM strains that had a gfp gene under the control of the ftsZ1 (−260 bp to −1 bp) or the ftsZ2 (−526 bp to −242 bp) promoter at the indicated light conditions, based on images as shown in Figs. S5 and S6. 100 cells of each strain from three independent experiments were measured. E Statistical analysis of aspect ratio, cell length, and cell width of cells of WT Anabaena and the ntcA mutant strains grown in BG11₀ with 5 mM NH4⁺ under standard light conditions for 24 h. The aspect ratio was calculated by dividing the length of the axis parallel to the filament by the length of the axis perpendicular to the filament. 200 cells of each strain from three independent experiments were measured. The mean value was indicated with the numbers. The Student’s t-test examined the differences between the WT and the ntcA mutant. Results were considered significant at *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, ns: no significance. F The transcription levels of the ftsZ gene in the WT Anabaena and the ntcA mutant grown in BG11₀ with 5 mM NH⁴⁺ under standard light conditions at 24 h. **p < 0.01. G Western blotting of FtsZ in the WT Anabaena and the ntcA mutant grown in BG11₀ with 5 mM NH4⁺ under SL conditions at 24 h.