Figure 3: Identification of mucR1/2 as negative regulator of PleC:CtrA promoters. | Nature Communications

Figure 3: Identification of mucR1/2 as negative regulator of PleC:CtrA promoters.

From: Cell cycle transition from S-phase to G1 in Caulobacter is mediated by ancestral virulence regulators

Figure 3

(a) Growth of WT (a) ΔpleC (b) and derivatives (c,d) carrying the pilA::PpilA–nptII transcriptional reporter on PYE plates containing kanamycin (20μg ml−1). (b) Immunoblot showing PilA steady-state levels in WT and ΔpleC ΔmucR1 double-mutant cells harbouring the empty vector (1 and 2, respectively), and ΔpleC ΔmucR1 cells harbouring either the mucR1- (3) or mucR1Tn5-plasmid (4). Molecular size standards are indicated on the left as blue lines with the corresponding values (blue) in kDa. (c,d) Occupancy of MucR1 (c) and MucR2 (d) at PpilA in WT, ΔpleC mucR1::Tn5 double-mutant and mucR1::Tn5 single-mutant cells as determined by qChIP using antibodies to MucR1 or MucR2. Data are from three biological replicates. Error is shown as s.d. (e) Immunoblots showing MucR1 and PilA steady-state levels in WT (a), ΔpleC (b), ΔpleC mucR1::Tn5 double-mutant (c,d) and ΔpleC ΔmucR1 ΔmucR2 (e) triple-mutant cells. The mucR1::Tn5 allele encodes a truncated derivative of MucR1. Molecular size standards are indicated on the left as blue lines with the corresponding values (blue) in kDa. (f) Immunoblots showing MucR2 and MreB (loading control) steady-state levels in WT (1), ΔmucR2 (2), mucR1::Tn5 (3) and ΔpleC mucR1::Tn5 double-mutant (4) cells. Molecular size standards are indicated on the left as blue lines with the corresponding values (blue) in kDa. (g) Regulatory network showing putative promoters (dots) bound by CtrA, MucR1, MucR2 and SciP as inferred from ChIP-seq results in WT cells (Fig. 2). Common targets between MucR1 and MucR2 are shown in purple, between CtrA and SciP are shown in turquoise and between MucR and CtrA in red. This last group is subdivided into those bound by MucR1/MucR2/CtrA (a), MucR1/CtrA (b) and MucR2/CtrA (c). Note that MucR1/2 and SciP have few common targets. See also Supplementary Data 8 for a prediction of specific and common MucR1 and MucR2 targets. (h). Scheme showing the predicted direct regulatory interactions at G1 or late S-phase promoters inferred from g.

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