Fig. 5: Crn4a neutralizes CRISPR immunity in a plasmid challenge assay.
From: Structure and mechanism of the broad spectrum CRISPR-associated ring nuclease Crn4
a Plasmid challenge assay. The expression of Crn4a increased cfu in cells with cA4-activated TsuCsx1 and cA6-activated MtbCsm6, consistent with degradation of those cOA species. For the Csm6-2 effector, however, no increase in cfu was observed when Crn4a was co-expressed. cOA was synthesised in the MtbCsm system programmed with crRNA targeting the tetR gene, while no cOA production in the MtbCsm non-target (pUC) system was set as a negative control (represented by ticks and crosses, respectively). Representative plates of two biological replicates with two technical replicates each are shown. b Schematic of the experimental design. c Colony counts for transformants in the presence or absence of Crn4a in the context of activated MtbCsm target system. Data are two biological replicates with two technical replicates each and are presented as mean ± s.d. Statistical analysis was performed using ratio paired t test (one-tailed P values listed from left to right on the graph: *P = 0.0399, *P = 0.0217 and nsP = 0.25). Source data are provided as a Source Data file.
