Figure 6
From: Methylomic and phenotypic analysis of the ModH5 phasevarion of Helicobacter pylori
ModH5-mediated methylation of the flaA promoter region at site GACC1 modulates downstream gene expression. (a) pTM117-flaA reporter construct carrying either GACC1 (wt promoter) or GCCC1 (A > C synonymous substitution mutant) was used to transform H. pylori modH5 strain 7.13 wt; “Epi” - total population of kanamycin-resistant transformants imaged by epi-luminescence (colonies false coloured red in ImageJ); “GFP” - fluorescent transformants imaged using a GFP-specific filter (colonies false coloured green in ImageJ); “Overlay” shows proportion of GFP-fluorescent transformants (yellow/green) to non-fluorescent transformants (red). (b) Sequencing of the modH5 G-tract in GFP-fluorescent (GFP +ve) and non-fluorescent (GFP −ve) transformants carrying pTM117-flaA with GACC1 versus GCCC1 showed that the correlation between ModH5 activity and P12 flaA promoter function was uncoupled upon loss of the upstream ModH5 methylation site (GACC1). P-values were determined using Fisher’s exact test; ****P < 0.0001, NS = not signficant.
