FIG 1.

PAI genes responsible for the loss of T4SS function in mouse-passaged H. pylori. When cagY PCR-RFLP showed no changes, amplicons were run on low-percent agarose gels to detect size differences (A). Examples of changed cagY size are shown in lanes 3 and 4. The PacBio sequence of cagY was unable to be verified with the Sanger technique due to its repetitive nature. Therefore, Western blots were used to detect changes in the size of CagY resulting from indels causing truncation (B). Lane 1, input WT PMSS1; lane 2, unchanged output strain; lanes 3 to 5, changed output strains. Changes were found most commonly in cagY, but all genes essential for cagPAI function were changed at least once except for cag3, cag4, cag18, and cag20 (C). No changes were found in genes that are nonessential for CagA delivery. Bars indicate frequency of changes during mouse passage for each gene that is essential for cagPAI function.