Fig. 1: CccR mediates both contact-dependent and contact-independent competition.
From: A secreted effector with a dual role as a toxin and as a transcriptional factor
a Schematic of a gene cluster encoding T6SS effectors in Yptb. Locus tag numbers are provided on the top of each gene, and the cccR gene (ypk_0951) is indicated in black. b Domain organization of CccR. The boundaries for the FIC (residues 49–210) and HTH (residues 295–346) domains are indicated. c CccR is toxic to E. coli. Growth of E. coli BL21(DE3) cells containing a vector control or a vector expressing CccR or CccRH192A under noninducing (no IPTG) or inducing (100 μM IPTG) conditions. d CccR induces filamentation of E. coli cells. Representative micrographs of E. coli BL21(DE3) cells expressing CccR or CccRH192A were acquired 10 h after induction of protein expression. Scale bar, 10 μm. The images shown in c and d are representative of three separate experiments with similar results. e–g Outcome of growth competition between the indicated Yptb donor strains and E. coli DH5α on solid support (e), in liquid medium (f) or by separating donor and recipient cells with a cell-impermeable membrane on the surface of solid medium (g). The CFU ratio of the donor and recipient strains was measured based on plate counts. Data in e–g are presented as the mean ± standard deviation (SD) of three independent experiments. P-values from all data were determined using a two-sided, unpaired Student’s t-test, and differences were considered significant at P < 0.05. Source data are provided as a Source Data file.
