Figure 7. Genetic experiments indicate DNA-mediated signaling among DinG, EndoIII, and MutY.

Left: When EndoIII is knocked out of InvA cells that depend upon R-loop repair by DinG for growth, a significant growth defect is observed (red). When the knockout, InvA Δnth, is complemented with a plasmid encoding WT EndoIII, EndoIII D138A, or RNaseH growth is restored (blue). When InvA Δnth is complemented with an empty plasmid or a plasmid encoding EndoIII Y82A, the growth defect remains (red). Taken together this indicates that the growth defect is indeed due to silencing the nth gene, that there is signaling between EndoIII and DinG to facilitate the unwinding of R-loops, and that this signaling is DNA-mediated; the enzymatically active but CT-deficient mutant EndoIII Y82A cannot restore growth while the CT-proficient but catalytically inactive EndoIII D138A does restore growth. Right: The InvA growth assay and Lac+ reversion assays tested indicate that DNA-mediated signaling facilitates signaling among DinG, EndoIII, and MutY.