Fig 1. CP upregulates the Zur regulon in vitro and detection of Zur-regulated protein expression in regions containing CP in vivo.

(A) Heatmap showing log₂FC values for genes in the Zur regulon after growth in media without added Zn²⁺ followed by short-term exposure to CP, TPEN, 6 μM Zn²⁺ and 500 μM Zn²⁺. In each condition the change in expression (log₂FC) is relative to the 6 μM Zn²⁺ condition. Log₂FC expression values are calculated from the normalized expression counts of biological replicates (n = 3). Confocal microscopy images of serial sections of lung granulomas at 20X magnification stained for Mtb ribosomal proteins with polyclonal anti-S18-1 (B) and anti-S18-2 (C) antibodies (red), CD68+ macrophages (green) and CP (blue). The field in B and C bound by the white box is magnified in panels Bi-ii and Ci-ii and corresponds to a region containing both CD68+ epithelioid macrophages and CP-stained neutrophils and caseum, as well as distribution of Mtb S18-1 (Bi) and S18-2 (Ci). Single channel images from staining with antibodies specific to Mtb ribosomal proteins only is shown for S18-1 (Bii) and S18-2 (Cii).