Fig. 1: AimR functions as an antiterminator of a transcript that initiates at aimP.
From: Antagonistic interactions between phage and host factors control arbitrium lysis–lysogeny decision
a, Left: schematic view of the regions cloned into the pDG1663+ Pspank reporter plasmid and fused to the β-gal reporter gene. The DNA sequence (top) shows the predicted terminator and the regions corresponding to the stems (blue) and loop (red). Right: β-gal expression was measured in B. subtilis strains carrying the construction after IPTG induction of the Pspank promoter. b, Predicted minimum free-energy secondary structures of the terminator for the wt and evolved sequence (RNAfold). Colours represent positional entropy in the structure. In a and b, the black arrow indicates the mutated base. c, Left: schematic view of relevant genetic features upstream from aimX and of the regions cloned into the reporter plasmid and fused with the β-gal gene. d, Top: schematic of the genetic features used to characterize cross-activity of AimR antitermination for SPβ and phi3T where the binding site has been swapped. c, Right and d, Bottom: β-gal expression measured in B. subtilis strains carrying the integrated reporter plasmid and pDR110 (empty or AimRphi3T) or pDR110 (empty, AimRphi3T or AimRSPβ) plasmid, respectively, after IPTG induction of the Pspank promoter in pDR110. In the schematics: black arrows, promoters; black lollipop symbols, putative transcriptional terminators; TT, transcriptional terminator; TT*, evolved mutated TT; BS, AimR binding site (red, phi3T BS; green, SPβ BS). ∆BS, mutated BS palindromes; Incr, increased distance between the TT and BS; Decr, decreased distance between the TT and BS. Data presented as mean ± s.d. (n = 3). In a and d, an ordinary one-way analysis of variance (ANOVA), followed by Dunnett’s multiple comparisons test, was performed; in c, two-tailed t-tests were performed. P values are indicated above each comparison: ****P < 0.0001; ***P < 0.001; NS, not significant.
