SWATH-MS demonstrates changes to protein expression due to a phase variable methyltransferase, ModA16, in Haemophilus influenzae biotype aegyptius

Cytoplasmic DNA methyltransferases are often associated with restriction modification (R-M) systems in bacterial systems. Phase variable expression of these DNA methyltransferase results in epigenetic regulation of multiple genes as part of systems called phasevarions (phase-variable regulons). H. aegyptius is the causative agent of Brazilian Purpuric Fever (BPF), an invasive disease with high mortality, that sporadically manifests in children previously suffering conjunctivitis. We have recently described a previously unidentified allele of a phase variable Type III DNA methylstransferase in H. aegyptius, ModA16. When ModA16 is expressed, H. aegyptius strains exhibit differential methylation throughout the genome compared to when ModA16 is not expressed. This change in methylation results in altered gene expression and SWATH-MS was used to identify the resulting changes to protein expression. This dataset represents triplicate repeats from strains which express ModA16 (ON) and strains which do not (OFF).